You can't add any altcoins in Bisq for years, it was officially put on hold, and I doubt there would be any volume for other coins without someone making a fake volume like on centralized exchanges.
Someone is working on Bisq fork exchange based on Monero, so there is a chance for listing more coins if that gets some traction and activity.
If you look at Bisq markets you will see that Monero currently have highest trading volume after fiat currencies like Euro, Pound and Brazilian Real.
https://bisq.markets/