xtiger is a free TI-92 emulator. It was originally written by Jonas Minnberg and was closed source. There were two versions: the SVGA version and an Xlib version. Jonas Minnberg has not worked on XTiger for quite a while and he gave me (Misha Nasledov) the code and permission to GPL it, after I asked him if there was any chance he would open source it.
xtiger uses GGI, which supports many methods of output including (and not limited to) SVGA, X, fbdev, and aa.