Quite a few. Discounting the shitty, internet-famous artists constantly stalking us for the next FotM to bandwagon on, we've had quite a few big-name creators pop in occasionally.
Justin Roiland is a filthy little shitposter who is likely constantly pushing the "Reddit and Memey" threads, Ian Quarterly and Rebecca Sugar used to visit the /sug/ flockdraws, and a chunk of that show's staff has likely visited the general at some point as well. Alex Hirsch was also around here occasionally, before running away like the flake he is.
The creators of Motorcity used to share their work here, and hung out for the premiere, while I'm pretty sure some of the folks behind Wakfu came to visit after we decoded their fantasy alphabet by translating the sign of an in-show brothel.