alolan forms are based on old ideas. eigther used old ideas or unused old ideas and/or fan myths. let's discuss those I am missing here:

(delta species in gen 3 pokemon cards might also be an inspiration in their brainstorming for gen 7 ideas)

alolan exeggutor (with long neck) appeared on gen 1 jungle booster box (set 2) artwork for japanese cards.

alolan pikachu was in the early anime. it was a surfing pikachu with psychic abilities to sense big waves comming.

alolan marowak is the fan legend of the mother being dead and the mother joins their kid as it evolves. (ghost type) the fire type is also a reference to charizard.

so what else?