"Do You Wanna Date My Avatar" was a music video they did before Season 3 (song co-written by Joss Whedon's brother Jed with choreography done by his now wife Maurissa who was one of the dancers, they now work on Agents of SHIELD).
There are two other The Guild music videos. One, a Bollywood homage called "Game On" before Season 4 and a more traditional MTV style video called "I'm the One That's Cool" that came out last year during the launch of Felicia Day's YouTube geek channel Geek & Sundry which has series including TableTop, a series hosted by Wil Wheaton on board games where he and other celebs, both TV and internet, play and evaluate games like Ticket to Ride, Munchkin, Settlers of Catan, etc. The Vlogs there are also fun. Currently everyone seems to be doing a Doctor Who 50th aimed Vlog.