Easily one of the best strategy games supported on Linux, Crusader Kings III from Paradox Interactive has a huge free update plus a DLC and some free to play time.
The 1.3 "Corvus" update went out which adds in a huge amount to the game including Winter. Yes, Winter is coming so you need to be more prepared than ever as the map gets a blanket of snow and there's a few different types. There's a new personal combat system that has characters have a duel, the Poet trait has been added to the game, an enhanced hair & beard inheritance gene system, a vast number of new Coat of Arms for Norse rulers, 8 new Norse-inspired Custom Faith icons and more.
Giving players a little more Norse, the Crusader Kings III: Northern Lords pack is also out now adding in:
- Norse Adventurer Realms: Norse characters may abandon their own homes and lead hosts into foreign lands to establish their own kingdoms.
- Jomsvikings and Shieldmaidens: Norse holy warriors and stalwart shieldmaidens take up arms on your behalf, while poets can compose stinging rebukes or romantic overtures.
- New Cultural Content: Special Norse dynastic legacies, Norse blot sacrifices, trials by combat and cultural innovations as well as numerous new events add additional color.
- New Art and Music: Original art and musical score to enhance your playing experience.
- And more: Berserkers, missionaries, runestones, Varangian adventurers, new decisions and other highlights from the exciting history of the Norse people.
From now until Sunday, 21st March at 5PM UTC you can download and play for free on Steam. Plus it's also 20% off until then too. I can easily recommend trying it out!