Honeywisp
Honey wisps carry nectar that pikmin drink to bloom. To get the nectar, throw pikmin at the shadow of the creature before it disappears.
Unmarked Spectralids
Hit these guys and they drop nectar
juvenile bulbmin
These creatures are related to the pikmin. they spend their days in certain caves. They follow a leader. You can get them for use in a cave only, by defeating their leader and calling them.