Cassette Beasts from Bytten Studio is a brilliant spin on the whole monster catching genre, and a fresh update out now continues expanding it.
The Gauntlet Update, version 1.7, has release and the first major addition is Magikrab's Gauntlet, a series of randomised combat encounters that can be played solo or online with a friend. And, to enhance things even further, modding should be a whole lot easier with Steam Workshop support now enabled for it.
Main New Additions:
Cassette Beasts has Native Linux support and is Steam Deck Verified. It's also just thoroughly cool, you should check it out. Another great one made with Godot.