As Bob notes, Badger exists but apparently only on the obscure end of piece names: Taikyoku has at least one kind, as does Man and Beast 20. Ofc since Taikyoku is in any case loose with its naming and Gilman's Badger is Hex‐prism‐exclusive so no problem there, and it's nicely mnemonic.
Likewise, Ram has some prior use, not only as the Advancer but also in a couple places as the Siege device, as well as in H.G.'s Megalomachy; since these are typically square‐board pieces it's perhaps a little more contentious.
Rat seems pretty much unused, if perhaps an odd animal to associate with rooklike moves
As Bob notes, Badger exists but apparently only on the obscure end of piece names: Taikyoku has at least one kind, as does Man and Beast 20. Ofc since Taikyoku is in any case loose with its naming and Gilman's Badger is Hex‐prism‐exclusive so no problem there, and it's nicely mnemonic.
Likewise, Ram has some prior use, not only as the Advancer but also in a couple places as the Siege device, as well as in H.G.'s Megalomachy; since these are typically square‐board pieces it's perhaps a little more contentious.
Rat seems pretty much unused, if perhaps an odd animal to associate with rooklike moves