I'm not aware of any list, but here are a few a few Cisco-compatible products:
Spectralink:
http://www.spectralink.com/products/netlink.html
IP Blue Softphones:
http://www.ipblue.com/products2.html
Tandberg videoconferencing solutions:
http://www.tandbergusa.com/index.jsp?flash=true
Clarisys USB Handsets etc (used in conjunction with softphone):
http://www.clarisys.com/
I seem to recall coming across another couple, but don't remember at the moment. Once CallManager supports SIP user agents (as opposed to SIP trunks), there will likely be more phone options.