I use these three graphics / UI mods, which I consider to be essential:
UI mod: The Eddy Vegas UI Mod - V3.1 small update
Map terrain mod: DasTactic Icons - Mroyer Terrain Combined Mod
Stratagem cards mod: [Mod] Pymous Shadow Stratagems Artpack (v4) - May 2021
EDIT: And these beveled unit cards, so I can more easily see multiple unit stacks: Beveled Units Mod (v4.1) - Critters Update