Ryanide wasn't exactly a celebrity, but he was pretty popular during his active days, not sure if many have heard of him, but he played a major role in getting the overall populace more accepting of furries. I'm assuming you mean people who never admitted to being furry before but came out, but I'm not sure.
Alvin-Earthworm wasn't either, he was well known for Super Mario Bros. Z, but pumped out large amounts of furry artwork.
It seems there's more brony celebrities than furry celebrities, interestingly. At least, the ones who've admitted. As 'noners said, they're probably worried about the tarnishing of their reputation.
Side note, that Andrew W.K. one, I didn't know, and I found that pretty darn awesome.