HoMM3
Heroes 3, probably still most successful game in the series, spiritual successor of Heroes 2, after all - it's based on the same engine. There also exists Heroes 3 HD by Ubisoft but it's missing both Add-Ons, Armagedon Blade and Shadow of Death - on the other hand, Ubisoft released it also as an Android game. Developed by 3DO and published by NWC. Among with Heroes 4, it have the best map editors which warranted thousands of maps and campaigns created. Recommended mod here is ERA2, which is "WoGified", meaning that it contains WoG, in a way. WoG 3.59 is still along the way but there is plenty of other fan mods, like Horn of Abyss. If you would like just the vanilla game, certainly install HD mod by baratorch. This one is already included in ERA2. Should mention also VCMI, which is not a mod but a new engine, with everything written a new, reusing game assets, adding new ones and having version for Android too.