Some of my personal favourites or I have never seen:
Aurelion Sol
Kha'zix
Omega-Xis
Kay/O
Genji
Warframe Chroma

Ooh Genji and Kay/O are good suggestions, Chroma looks super cool too but I don’t play warframe so it’d probably be a little difficult

I also just remembered Revenant from Apex. I have never seen anything with him.
And SCP-049 the Plague doctor

Plague doctors make me augh and Revenant was my favourite character from Apex when I used to play so these are really good suggestions, thanks man!

I like Warframe, a bit too grindy but I like playing it from time to time.

In no particular order:
Baymax (Big Hero 6)
Papyrus (Undertale)
Man Ray (Spongebob Sqaurepants)
C-3P0 (Star Wars)
Pyro (Team Fortress 2)
Cannonbolt (Ben 10)
King Boo (Luigi’s Mansion)
Master Kohga (Legend of Zelda)
Darth Vader (Star Wars)

Ooh I like these ideas too, Baymax is an especially good one

I can think of many sagas which characters aren´t pretty poular on the tf stories but could be a great material for them in my opinion

- rampage total destruction characters

- Crash bandicoot villains like koala kong or tiny tiger

-Yo kai watch (blazion is one of my favorites)

-Ok ko (like rad or bernard)

-Mystery skulls, specifically because of lewis ghost form

-Many of the dark deception monsters (they could go well in a horror mc tf story)

-Persona series ...err.. personas?

-Road rovers characters

-Cuphead bosses

-Spooky jumpscare mansion specimens (horror tfs again)

-Dragon ball (there´s a lot of furry material)

There are some more but i think i extended WAY too much the list haha

I plan to probably write a story with Tiny and Bergamo at some point and if I wrote a story on the specimens it’d probably be 2 or 8

I do have a few suggestions if that is alright
Eugen (Granblue Fantasy)
Omni Man (Invincible)
Wakatsuki Takeshi (Kengan Ashura)
Shiva (Record of Ragnarok)
Yami Sukehiro (Black Clover)
All Might (My Hero Academia)