I use a meta team that includes Irongut + Essence of Evil, so these are the notes I made when I reviewed all the kingdoms:
Ghulvania - watch for: Undeads are immune to poison/disease; BUT YOU CAN EAT THEM ALL
Glacial Peaks - watch for: Freezing is a b; Can’t eat DOOM but everything else is lunch
Khetar - watch for: Faction troops cause bleeding; Undeads are immune to poison/disease; EAT EVERYTHING BUT War Sphinx
Mist of Scales - watch for: Snakes cause poison/bleeding; Bogstrider causes entangle; EAT EVERYTHING BUT Euryali and Plague Rat
Pridelands - watch for: EAT EVERYTHING BUT Behemoth
Silverglade - watch for: EAT EVERYTHING
Swords Edge - watch for: EAT EVERYTHING
Whitehelm - watch for: EAT EVERYTHING
In the end, I picked Whitehelm because when the game loads, it’s right in front of me. It’s also my “home” kingdom.