While OpenTESArena is still a work in progress to bring The Elder Scrolls: Arena up to modern standards, it's looking even better with the 0.17.0 update.
GE-Proton 10-17 was just released following on from GE-Proton 10-16 a few days ago, to further enhanced Windows games on Linux / SteamOS and Steam Deck.
Valve updated Proton Experimental for September 19th, adding their usual assortment of fixes for running Windows games new and old on Linux PCs and Steam Deck.
Warzone 2100 continues living its best life as a free and open source project, with the classic RTS receiving another major upgrade with version 4.6 out now.