The following is true for every official D&D setting.
Players Handbook (page 205):
"
The worlds within the D&D multiverse are magical places. All existence is suffused with magical power, and potential energy lies untapped in every rock, stream, and living creature, and even in the air itself. Raw magic is the stuff of creation, the mute and mindless will of existence, permeating every bit of matter and present in every manifestation of energy throughout the multiverse."
"
Forgotten Realms calls this suffusive "magical energy" the Weave, but exists in every D&D setting.
That said, later 5e products have mentioned the Psionic power source, in addition to Arcane and Divine. Primal is defacto a power source for Druid and Barbarian.