Oathbound: Plains of Penance (2002)

From the back cover:

Beyond the most populous city on the Forge lies a vast, uncontrolled expanse of rolling grasslands, scattered crags, and light woods. In strong contrast to the rest of the world, where nature stands in opposition to intelligent life, the bountiful land here provides a lush wealth of resources upon which the great cities have come to depend. Powerful forces vie for control over this abundant domain, as ruthless bloodlords of the cities clash against the deep-rooted druids of the wilds, hardened armies from the west, and even mysterious visitors from the depths of the northern oceans.

Within the Plains of Penance, you'll find:

- 5 new player-character races
- 5 new prestige races
- 2 new prestige classes (Artificer and Disjoiner)
- New magic items, monsters, spells, and weapons