This is my own interpretation of what 'Reality' magic would be, so take it with a grain of salt. Disclaimer, this is not the concept that I make, but something that I picked up from Gu Zhen Re's Reverend Insanity.
A bit of context: in Reverend Insanity, cultivation (in this book, it is the use of Gu Worms) are categorized into 'paths'. For example, cultivation methods that related with the element of fire would be fire-path, anything related with metal are metal-path, so on and so forth. Naturally, there's also non-elemental path such as sword-path that, like its name, are completely related to swords, there's also wisdom-path that focuses on how human think (thought, will and emotion), formation-path, time-path, painting-path, strength-path etc etc.
Now, what I think is very similar to the 'reality magic' that you wanted is the path invented by one of the most powerful character in Reverend Insanity, his name is Limitless Demon Venerable: rule-path.
Just like it's name, rule-path relates to the manipulation of 'rule' or the 'laws' of heavens and earth. Rule-path Gu Worms have effects something like this: enlarge, shrink, multiply, good, bad, strong, weak, straight, curved, close, far, truth, lies, round, square, et cetera. For example, the gu worm 'strong' has a function to strengthen a killer move (you can think killer move as a spell in this book), or the gu worm 'straight' could make a killer move's vector linear. The application of rule-path gu worms are so adaptive that it is adopted in other paths.
If my comprehension are correct, then 'reality magic' should be similar to rule-path.
Example 1: the speed of sound is roughly 343 m/s, but using 'reality magic', you can somewhat bend the rule to accelerate it into 700 m/s.
Example 2: the weight of pure water is 1 gram/ml, or 1 kilogram per liter, but using 'reality magic' you might make water 10 kilogram per liter.
Example 3: the density of steel is 7.85 gram/cm3, but using 'reality magic', you can make it so 19 g/cm3 (density of gold)
These examples are if you want to use scientific approach.
These are my opinion on spells that should be related to 'reality magic'
1. Reflection: In Dota 2, the item 'Blade Mail' reflect damage that the user received to its source. This might be a good 'reality magic' since it works on the rule of 'reflection' which was not elemental in nature.
2. Metamagic: in DnD, there's a mechanic called Metamagic that could somewhat alter spells. For example: Extend, Lengthen, Subtle, etc. In Overlord, there's also the same Metamagic spells like Boost Magic, Delay Magic, Maximize Magic, Triplet Magic, Widen Magic, etc etc. Instead of making original 'reality magic', what if reality magic manipulates magic instead?
3. Anti-magic: in Toaru Majutsu no Index, Imagine Breaker in Touma's right hand allow him to negate anything supernatural like esper, magic, or god's miracle. This is the usage of the concept 'denial', which was not elemental in nature so this might be a good 'reality magic'. A similar concept is Rule Breaker, which is a Noble Phantasm of a Caster-class Servant in Fate Series, which allows the user to nullify every kind of magecraft in the world.
Etc etc, hope this helps.