Unit Addon is a mod for Europa Universalis IV, created by Gnhtd.

Description:

It’s a small, but useful project that adds tons of new unit into the game. Practically every playable faction was enhanced this way and everything got balanced properly, so the new additions don’t overpowered the existing units.

To install:

Extract into “...Steam\SteamApps\common\Europa Universalis IV\mod” and activate in game’s menu.