My main suggestions are Shikamaru Nara (Or the nara family as a whole) from Naruto.
Pride From Full metal Alchemist: Brotherhood (Anime).
Fumikage Tokoyami from Boku No Hero.
the MC from Solo Leveling (Manhwa - Light novel) could be used as example depending on how you see his powers, if you don't know what I mean and only watching the anime...well, Look forward to chapter 12's ending that should give a glimpse of what I mean xD
Nach Faust from black Clover.
And Finally...one of my favorite uses: Celty Sturluson from anime Durarara!!
In general the homunculi from that series could all work depending on the flavor of Shadow Magic you use, or what you intent to make out of it.
Is it more on the esoteric side? (Fear of the unknown, monsters, eldritch abominations) Then Pride, Gluttony, And Envy from FMA: Brotherhood are what you need to take inspiration in powers.
Is it more based on the elemental aspects of manipulation? Then Shikamaru from naruto is your best bet (Pride from FMA still qualifies tho), Celty, Nach and Fumikage.
And as a shameless plug, my MC from my series uses shadows as part of her skill set. She is a somewhat weird combination that takes just a smidget of what I like of the shadow powers, elemental manipulation, sumoning and creates weapons from the shadows she uses (Click the meme ad or the title if you want to take a peek, the meme ad sends you to RR and the text sends you to the link here in SH)
As I said, it mainly depends on what you want to do with those powers. I would advice you to just write what you want and don't let yourself be beholden by the expectations of others...BUT if you end writting a shadow user with one of those sources I gave, do tell since I love shadow based powers ;3 (As you could guess by my MC using Shadows as part of her powerset)
