Tactical strategy are probably my favourite game type. I’ve spent a lot of time playing these:
UFO:AI, the community-built version of X-COM, http://ufoai.org/wiki/About
Expeditions: Conquistador, http://store.steampowered.com/app/237430/
Fallen Enchantress, http://store.steampowered.com/app/228260/
Legends of Eisenwald is also shaping up, though still has some way to go, http://store.steampowered.com/app/246760/
7,62: High Calibre, not exactly turn-based, but very fun still, http://store.steampowered.com/app/289890/
But now I’m very enthusiastic about Battle Brothers. :)