I think this question is aloud because I am trying to make a strategy with pokemon who can learn multiple types of moves.
Mew can learn all TMs and HMs Arceus can learn all HMs and all TMs except for 1, 8, 12, 28, 41, 51, 54, 56, 63, 64, 69, 74, 78, 88, and 89.
/ds learnsalltypes [mew, smeargle, jirachi, drampa]
source I think this answer is likely to be complete because I looked at old tutor moves and event moves, but I didn't look at gen 8. Kangaskhan, Aggron, Rayquaza, Giratina, and Arceus can learn a move of every type in gen 5, but they can't learn a fairy move in newer games.
Smeargles sketch could learn every move.