I am not too familiar with this series but it is piquing my interest.
Warlords III! Finally! One of the best turn-based strategy games of all time. Also, some of my favorite music in any game!
Warlords 1 to 3 are published by Slitherine on GOG.Wishlisted. Too much other stuff to get in this week's mid-week sale, but I had a ton of fun with II and III back in the day.
For those who don't know: think of HOMM with automated battles that are decided based on who has stronger units.
I wish Ubi (I think they own the IP?) would commission an RPG in the world of Etheria. If you played Warlords BattleCry III and Warlords 3 + 4, there's a really interesting world there with some cool lore to explore.
EDIT: Etheria, not Erathia. Erathia is the Castle Kingdom in HOMM3