Do you use a Newtek TriCaster? If so, you're in luck! We've pushed an update to Unity Server that now supports tally from a TriCaster. Just like with the Blackmagic Atem mixers, you just select Newtek TriCaster for your tally mode from the tally pulldown and enter the IP address of your mixer (once you've purchased the Tally upgrade, that is). We've also upped the number of tally inputs from 16 to 64.
If you're running a Ross, Grass Valley, or Sony mixer that supports tally over TLS TallyMan protocols, you're next on the list!