Developed by Ludic Studios (Akane), they just recently announced their new game Wind Runners. It's a side-scrolling dogfighting roguelike and it does look pretty sweet.
Developed by the Ukrainian solo outfit Muzt Die Studios, Knightin'+ is a real-time 2D dungeon crawler with a simple pixel-art style and streamlined gameplay. They're calling it a "Zelda-lite adventure".
Easily in my top five releases this year, Streets of Rogue from Matt Dabrowski and tinyBuild has now left Early Access with Linux support in good shape.
Developer Obscure Tales emailed recently about their intriguing pixel-art survival horror "Lamentum", they're planning full Linux support and it's currently crowdfunding on Kickstarter.
TheoTown, developed by blueflower is a city-builder with a retro style that looks to be inspired by the classic Sim City 2000 and it's now available on Steam for Linux.
Due for release sometime this Summer, Children of Morta looks like it's going to be a huge amount of fun and thankfully the Linux version is still confirmed to be coming.
Eagle Island, a game where you run around and throw your loyal owl companion at your enemies (yes really, it's awesome) is set to release on July 11th.
Currently in development by Hungry Pixel, NetherWorld has a pretty impressive pixel-art visual style that will mix insane action with narrative elements and it's coming to Linux.
Hyperspace Delivery Service, a very sweet looking pixel-art space trading and adventure game has officially released and comes with full Linux support.