Planned to be released on Steam and GOG (if GOG approve) after an upcoming Kickstarter campaign, BOC seems like a very interesting turn-based 4X coming to Linux.
Interesting for more reasons than just style and gameplay, as developer Code::Arts say they've worked on their own multi-platform OpenGL/Vulkan game engine they've called the Deus Ex Machina engine. Their aim with it, is to have a game engine that focuses on "performance and the efficient use of resources" so that it could "run on a toaster". Starting development back in 2018, their current aim is to have something playable and ready for Early Access next year.
You can see more videos of their progress on YouTube.
More about it:
BOC is a realistic historical turn-based 4X strategy game. Unique features like 360º realistic worlds on a global scale are brought to life by our performance-focused multiplatform engine, hardcore tactical components, and climate simulation. Our approach will take players through the ancient world, starting in the Ice Age (55.000 B.C) up until to era of great ancient empires and the fall of the Western Roman Empire.
What also piqued my interest about BOC, is that you're not given some pre-defined civilization or culture to follow. Instead, you start off with a tiny tribe and eventually grow into something much bigger. They're going with a more sandbox approach to it, so your civilization changes as it grows with your decisions. The world is as dynamic as your civ, lands that change over time due to rising sea levels, ice melting and more.
Definitely one to watch, could be something special in the works here. You can wishlist and follow on Steam. When the crowdfunding campaign goes live, and if GOG accept them onto their store I will let you know.