Paradox Interactive games are known for their depth, replayability, and robust modding communities, and they are currently available for huge discounts on Steam until May 15.
Europa Universalis 4 is recommended as a strong foundation game for both newcomers and veterans, with the base game priced at $4.99 and the Starter Edition priced at $11.99 including 10 DLCs.
Victoria 3, focusing on modern history and economic management, is available at a 70% discount for the base game at $14.99, while the Starter Edition with the Victoria 3: Sphere of Influence DLC is $32.49.
Stellaris, preferred for interstellar conquests, is considered Paradox's most accessible grand strategy game and is on sale until May 19, with the base game priced at $9.99 and the Starter Edition with 3 DLCs at $15.99.