Tales of the Old Margreve is a collection of forest-themed adventures. The OGL content includes the new monsters in the Appendix.
OGL Content:
Bulbous Violet - (monster)
Colláis - (monster)
Golem, Vine - (monster)
Lunarchidna - (monster)
Lunarchidna, Greater - (monster)
Lunarchidna, Lesser - (monster)
Lunarchidna, Transcendent - (monster)
Piney - (monster)
Piney Rootwalker - (monster)
Stormboar - (monster)
Tree Skinner - (monster)
Tsuchinoko - (monster)
Vallowex - (monster)
Wraith Bear - (monster)