In Monvesia, there are both mystics and wild talents (members of other classes who have developed psionic ability).
Wild TalentsWhen I saw the Great Old One patron for the 5th edition warlock, I saw how psionics could be incorporated seamlessly into the existing rules. While the mystic has been evolving well into a primary manifester, psionics can still be an option for characters that pursue other classes. Such "manifesters" (to borrow the 3.x term) are called wild talents. In a world where psionics are rare, wild talents are more common than mystics.
- Pursuing a Great Old One (the creators of the Taint) leads to an otherworldly pact
- Surviving the Taint can lead to a sorcerous origin
- A good option for halfling and half-orc characters
- Even my variant Eldritch Knight (the "Sentinel") is essentially a wild talent under this system--using Enchantment and Illusion instead of Abjuration and Evocation.
For full details, see "Savants of Monvesia."