-- RoR Upgrade: upgrade into special units (RoR, provincial, grudge settlers).
-- Expanded Chaos Upgrade: provides comprehensive upgrade options for Chaos.
-- Cross-Race: upgrade foreign units from ally / vassal / mercenary; Norsca marauder to chaos version; Chaos Dwarf laborer to greenskin units, etc.
-- Mods Compilation: A single pack that provides warband supports for many popular units / race mods, and some widely requested non-lore upgrade for vanilla units.


-- SFO + Warband
-- Radious + Warband Upgrade


-- Warband UI Framework: this framework prioritize the UI file, ensures best compatibility with all other warband mods, and provides two-column tab placement. For modders, the UI framework also enables warband support without requiring the main mod.
-- Warband Legacy: this is an old version from pre 3.0, with smaller UI size. It still works fine on its own, and good for small screen or old game version. It apparently has no new units / race since then, and maybe incompatible with all other warband submods.


-- Guns of Empire Upgrade.
-- Highborn Elf Upgrade.
-- Dragon Legion Upgrade.
-- High-Elf Compilation.
-- and probably many more.


-- Immersive Bretonnia Upgrade.
-- Bretonnia Vow Auto Complete.
-- Better Alliance: no more forced alliance breaking, and red-line skill benefits allied units.
-- Better Alliance - Agents : recruit foreign agent from allies.
-- Better Elites: resized and better elite units for meaningful upgrade.


If you are mod author & would like to make your units upgrade-able, here is a Simple Guide.

It covers how to add units to existing chaos groups; how to add units to other races; how to use the UI category in this Warband Upgrade mod.