Divided We Fall is a close-combat WWII multiplayer game about building a good squad and executing well thought-out tactics. It has Linux support and you can try it free for 2 days. Right now it's broken for me.
Always frustrating to see this happen. Battle Chasers: Nightwar, an RPG I was quite excited about has silently removed all mentions of Linux support from both Steam and GOG.
Project Zomboid is the impressive Zombie survival game that has single-player and multi-player that's been in development for a long time. This new release adds in quite a lot and vehicles should be next.
Railway Empire is a new simulation game coming out next year from Gaming Minds Studios and Kalypso Media Digital. It will have Linux support and they've released a new video to show it off.
While 'asset flips' are becoming a common occurrence, pre-made art assets are still a valuable resource when used correctly. Asset Forge and Kenney assets might be quite useful!
Take this with a rather large bag of suspicion! Netmarketshare is reporting that Linux had 6.91% market share, which is higher than Mac for the first time.