I'd say Realms of Arkania, however given that I had to look up what it's actually called outside of german speaking countries (it's the "Das schwarze Auge" over there), makes me think it never got quite popular on an international market. Maybe the followup game 'Drakensang' got more recognition?
Realms of Arkania 1-3 are available on GOG. Also, GOG's version of Icewind Dale comes with all the expansions (someone had recommended getting the expansions with it).
I also remembered a couple other freeware indie RPGs that have a lot of party customization, but they're not very "fast-paced"... more of a slow, tactical combat focus. But they might be worth checking out. The first is called Natuk and has you leading a band of eight orcs (or half-ogres) and generally running around being evil. You get to create the entire 8-member party with a lot of customization. But it has a complex, turn-based combat system that might be too slow for your tastes.
The second game is very similar in its combat mechanics. It's called Helherron, and features even better party customization due to a huge slew of races to choose from. It's hard though, and every single fight is a long, turn-based affair so again it might be too slow for your tastes.
I played both of these for a bit but ended up getting bored... but they do have very good party customization.
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