I think it matters what feats you have as well as the class.
Now, being an assassin is suboptimal because the assassin spell list sucks. I would go with being an erudite because it includes all arcane spell lists. Also, if you are using PH2, you can abuse the bloodline rules along with the ghostwalk class of eldonmancer. However, I will respect the request of the original post.
Weapons for an assassin: Poisons
You can't beat Abolth Mucus.
An aboleth underwater surrounds itself with a viscous cloud of mucus roughly 1 foot thick. Occasionally this substance finds its way into marketplaces. Glass vials of the mucus can be thrown as splash weapons. Any creature coming into contact with or inhaling this substance must succeed on a Fortitude save (DC 19) or lose the ability to breathe air for the next 3 hours. There is no splash effect for aboleth mucus. Save or die for 20 gp at a fortitude save DC 19? Broken. Just flat out broken. Cheap as hell and instant death for most living targets, because it requires cure poison and no amount of anti-magic or dispell will save your ass. And remember, it takes away the ability to breathe air, but does NOT give you the ability to breathe water!
What better way to use it than, The Alchemy Blade!
An alchemy blade appears much like a normal short sword. Two slender channels form a groove on each side of the blade, and the pommel is built to accept a flask of either alchemist’s fire or alchemist’s frost. Now being from Ebberon, it has been established that you can put poison in it, so why not your Abolth Mucus?
Also remember that you can add the WSA Assassin, which allows you to add the save of the weapon to the poison's DC as well automatically add poison to said weapon.
Or how about if you need to pretend to be a priest?
How about the aspergillum?
The heavy aspergillum combines the properties of a common aspergillum with those of a heavy mace and is greatly favored by members of the Impilturan church of Ilmater. A heavy aspergillum can hold up to 3 flasks of holy water. In addition to serving as a common aspergillum, it can also be used in melee combat. When a button on the shaft is pressed, tiny holes open in the mace head, allowing holy water to touch a creature struck by the weapon. Each use of the weapon in this manner uses one flask of holy water per attack whether or not the attack is successful.
Who says it has to be holy water? If it's fluid, you can use it.
But maybe you REALLY need to fuck someone up with poison?
Well, you can't beat the BLOODSPIKE!
A bloodspike somewhat resembles a thin potion vial, narrowing to a needlelike point at one end. The interior of the slender tube is filled with one of several varieties of alchemical substance (see below). To use a bloodspike, a user jabs it directly into her flesh (the fleshy part of the arm is an ideal location). Doing this deals 1 point of piercing damage (damage reduction does not apply when using a bloodspike) and causes the fluid in the narrow vial to be absorbed directly into the user’s body. Alternatively, a bloodspike can be thrown as a ranged weapon with a range increment of 5 feet. The bloodspike deals 1 point of piercing damage if used in this way, with the target subject to the effects of the bloodspike’s contents on a successful hit.
So not only can you put ingestion poison in this thing, if you made your bloodspike with the weapon special ability Assassin, you can put poison on the outside of the spike, so each spide injects your target with two forms of poison! I recommend Con drain with Abolth Mucus, because you get to apply the poison in the order you want, and what better way to kill someone than a poison that takes away the ability to breathe, while including a Con (thus fortitude save) debuff?
But lets move away from our mucus for a while and look at useful weapons for the steathy fellow.
WEIGHTED CLOAK
This cloak has an unusually thick lining at the bottom, which is filled with lead shot, a thin chain, or some other weight. When held with the other end wrapped around the hand, it can be wielded much as a flail, including bonuses to disarm and the ability to trip. DC 25 to find.
I’m going to beat you to death with my cloak. That has to be one of the worst ways to die. I mean, seriously. How do you explain that to anyone? “Yes ma’am, the gnome beat him to death with his clothes. No, he didn’t strangle him, or anything. He just… flapped him to death.” Now, here’s where it gets weird, can I wield two cloaks? Expensive, but a martial weapon all the same, so no extra feat cost. I see no reason any fighter worth his salt doesn’t have one of these, just in case. And you can trip and disarm as well. Make it red and call your PC “The Bullfighter!” And then use a weighted cloak to attack, and use the gnome battlecloak as a shield for the +4 to disarm attempts. Total +6 to disarm and you can do it with your primary or off hand. You’ll be a disarming fool!
Do not forget your Dust filled egg shell grenades!
A favorite tool of ninja, used to create distractions, eggshell grenades are emptied eggshells carefully packed with various alchemical substances. A dust grenade that hits its target directly blinds the target for 1d4 rounds. A creature within the “splash” radius of the dust cloud (5 feet) must make a Fortitude save (DC 10) or be blinded for 1 round. Naturally, eggshell grenades are very fragile and must be stowed carefully to avoid breakage. If a character carrying these items suffers damage from falling, each eggshell grenade must make a Fortitude save (as if the character were making the saving throw) against a DC of 10 + the amount of damage suffered. Eggshell grenades are too light to be used in a sling or other launcher.
Poof! Blind attacks are nasty, the problem is having the item last long enough to use it. Fixed with extra-dimensional storage. The save sucks, but read it carefully. The main target doesn’t get a save, only the splash targets. No save touch attack blindness for 1d4 rounds. Awesome. Just Awesome.
For magicing it up, nothing goes better with this than the WSA Exit Wound!
What happens when you buy this on something that clearly was never intended to go through people? The answer is, everyone in a line gets blinded and it does 1d6 points of damage to each target. Scary.
Of course there is the FInger blade. Yes, it is only 1d6, but it gives you a built in 1d6 sneak attack damage with a critical multiplier of x3. Alas, it is an exotic weapon, requiring a feat to use, but it is worth consideration for an assassin character.
The Flind Bar is lso worthy of consideration when you work as a team. Why? because on a critical hit, you get a free disarm attempt. Can't beat that with a stick, my friend.
Digging deep into 3.0, we come up with the fukimi-bari or mouth darts. You can hold three of these in your mouth and spit them at people, not much damage, but when combined with WSA assassin, you don't have to worry about poisoning yourself, and can ruin someone's day when you can't have weapons by any other means. (Like when going to a party)
And what assassin doesn't like a Garrote?
why, the LOCKING GARROTE!
This nasty variant of the wire garrote comes with a pair of metal grips, each of which contains one portion of a locking mechanism. Once the garrote has begun to deal damage after a garrote attack, the attacker can link the two ends and twist the grips into their locked position. This maintains strangling pressure on the victim even after the attacker lets go. The victim continues to make grapple checks (each one opposed by the last attack roll the attacker made) until freed or unconscious. The DC for the Disable Device check to free a victim from a locked garrote is 10 if the character attempting the task has Exotic Weapon Proficiency (locking garrote), or 25 otherwise. If someone other than the victim makes the attempt, a –5 circumstance penalty applies to the check unless the victim is
held, unconscious, or otherwise kept from moving. A character attempting to remove a locking garrote from his or her own neck suffers the same penalty on the Disable Device check, this time for working blind. Naturally, it’s impossible for any character to take 10 or take 20 on this check unless the victim trapped in the device is already dead. Smashing the locking garrote leaves it frozen in the locked position.
Consider the WSA explosive. Sure, you’ll get caught in the blast the first round, but after that, the target explodes every round until he gets it off. Sucks to be you! Just a side note, I don’t know why it isn’t a two handed weapon. I can’t see using this with one hand, although technically you can. Yes, that means you can DUAL WIELD locking Garrotes and hit a target TWICE in the surprise round! When you REALLY want someone to die choking, Dual wield this fucker and ruin your target's day.
Of course, you can use the classic Katana, but why use an ordinary katana... when you can use..
THE KAKITA KATANA
The master smiths of the Kakita family claim that they produce the finest blades in the Empire. A Kakita katana is made of exceptionally fine steel, durable and flexible, and is able to withstand the passage of a thousand years. The master smiths use only Hida steel in their blades, claiming that it far outshines any other in the Empire. A Kakita blade is distinguished by its light weight and flexibility, and by the fine lines of bluish damask running down the cutting edge, causing the entire blade to shine with a slight tint. These blades are usually bestowed only upon samurai who have proven their honor and courage, and only very rarely upon samurai who are not of the Crane clan. A non-magical Kakita katana has a natural +2 enhancement bonus.
That's a +2 EB WITHOUT SPENDING ANY OF YOUR WSA LIMIT! So you can instead of wasting EB on bonus to hit and damage, you can pour those points into WSA, like Extra damage, burning, acid, Haboob, or any of a few dozen broken weapon bonuses.
Now of course with you are using that, you want the Ninja-To
The ninja-to—a short, straight sword similar to a wakizashi—is the standard sword of the ninja. True to a ninja’s methods, the scabbard of the ninja-to is a multipurpose tool. It is open at both ends, allowing it to be used as a blowpipe for powders or poisons or as a breathing tube. It is also stiff and strong, allowing it to be used as the rung of a ladder or even as a weapon (use the statistics for a club).
Is it a nice weapon, but the scabbard is what’s impressive about this. It’s a rare triple weapon. A Shortsword, a club and a blowgun. While the three weapons are not that impressive, it gives to many options, which is what ninjas need
Or how about... The OCANTHUS KNIFE?
Ocanthus knives are actually alchemically stabilized shards of magically charged black ice gathered from the fourth layer of Acheron. An ocanthus knife has all the melee weapon characteristics of a dagger, except for the following: On a successful strike, a Medium ocanthus knife deals 2d6 points of damage (a Small knife deals 1d8, and a Large knife deals 3d6). After striking a foe, the knife loses its stability and immediately shatters and melts, gone but for telltale oily residue.
Very expensive for a one use item. Under the rules, a version of this knife that wasn’t one use would be 22,500 gp. That’s a boat load of gold for only 2d6 damage. That said, it’s a one use knife which means you can enchant it like ammunition. So if you plan on killing someone and you are going to do it in one shot, and you don’t want a weapon to exist afterwards, this is the weapon for you. May I recommend assassination and slather on the nastiest Con damage poison you can find? Hell, add poison WSA on top of that. Also, it’s ammunition and a melee weapon, so that should lend to some interesting combinations. And don’t forget that daggers have range. May I recommend exit wound as well?
or one of my favorates... RATLING TAIL SPIKES
A nezumi or vanara character who has proficiency with tail spikes can use them to make one extra attack in a round at her highest base attack, in addition to all attacks with a hand-held weapon (or a ratling’s natural weapons). The tail spike attack and each other attack made that round suffer a –2 penalty apiece. For example, at 6th level, Min’tchap gets two attacks with her nagamaki at +8 and +3 (including her strength bonus and Weapon Focus feat). If she uses tail spikes in addition, she gets three attacks: two with the nagamaki at +6 and +1, and one with the tail spikes at +6. This penalty applies for 1 round, so it affects attacks of opportunity the rattling might make before her next action.
Extra attack you say? Buy with Opposable and stick it on your butt. AWESOME! Of course it takes a feat to use, that’s why you buy it with aptitude or something. Sure it’s only 1d4, but with a high enough strength bonus, it won’t matter. Or sneak attack. Or a half dozen different things. And if you are asked to disarm, you can drop your hand held weapon, without anyone expecting you to attack them with your ass!
How about when you are running away?
Caltops. Never forget your caltrops, but follow that up with a Tanglefoot bag.
Between the two, people following you will be reduced to 1/4 speed.
If you want to be real sneaky, there is THE TOXIC TOOTH
Since the invention of alchemical capsules, researchers have continued to develop ever smaller delivery devices. The current peak of achievement comes in the form of the toxic tooth. Made to look identical to its wearer’s actual teeth (including the addition of plaque, random filth, and gaping cavities if necessary), a toxic tooth can hold a single dose of a contact or inhaled poison. To activate a toxic tooth, the wearer must bite down hard enough to crack it, then spit or exhale the poison at an adjacent creature. Doing so requires a standard action to make a ranged touch attack, but does not provoke attacks of opportunity. If the attack hits, the target is exposed to the poison and must save normally. Activating a toxic tooth also exposes its wearer to the poison.
And finally we come to, the humble whip.
Which in and of itself sucks, but if you combine it with whirlwind, it allows you to make a trip attack to everyone within 15 feet. Now if you increase the weapon a size class and then get the monkey grip feet, you can extend that out to 30 feet. Knock entire platoons on their ass so you can run like hell when you get surrounded. A bit of a hail mary, but still worth consideration.
While I did get into magical properties you could put on the weapons, I didn't give a full list of possible WSA, because, well, there are so many options.
I would direct you to my Encyclopedia Vinculum Draconus.
Here is a link to the zip file
Just chock full of every possible permutation of weapon, magical enhancement, well... everything. Seriously. EVERYTHING.
So if you are looking for crap for a character, it's all in there.
Even if you don't play d20 3.0/3.5, if you are just looking for ideas, you are looking at a zip file with all the items, magic spells, powers, feats, EVERYTHING, you need for d20 3.0/3.5. If you are saying, "I am writing a story and I want to consider different types of weapons" Well, have you considered the six-handed scissor sword? Only got two hands? Well, I explain how you can DUAL WIELD THIS MONSTER. Or why stilts on a frog are game breaking. Buku wierdness. Youknow I should make this it's own thread.