In the next story arc, the party are heading down through some old Dwarven mines, so naturally they're going to come across a few underdark beasties, namely the Intellect Devourer.
Currently, they are all level 5 and will likely remain so while doing this arc. What options do the players have for reversing the effects of Devour Intellect?
I am interested in all of the ways that this can be reversed, preferably starting with options available to second-tier parties. (Character levels 5 through 10, p. 10, Basic Rules).