Request from gastornis: my interpretation of Deinocheirus. I’m pretty sure it’s just a big ornithomimosaur, seems like the most likely thing to me. I gave it stockier legs than usual ornithomimosaurs, and I imagine it as being a more solitary animal (ornithomimosaurs always seemed gregarious to me). Gave it some emu-esque feathering on almost all of it, barring the legs (similar to ostriches).
If Deinocheirus is an ornithomimosaur, then almost all coelurosaur groups have at least one exceptionally large form, except alvarezsaurs and compsognathids (unless you count Sinocalliopteryx as a giant).