For me:
Nanaki/Red XIII
I had a crush on this fellow when FF7 came out, back in the stone age. Which goes to show the power of polygons! ...And imagination. :P
And I mean actual quaddy Red. Not the anthro-fied hyper-muscle or human ween versions.
Any Chocobo
What? These horsebirds are adorable!
Kaa
Most his art seems to be m/m (Nothing wrong with that. Just not my thing) or feet, tickling, or non-lewd hypnosis. So I always wish there was more of him with a lady or two.
So what are some critters/characters some of y'all wish had more lewd art?