[MMM]

SURU (to do) is the most common, but is also irregular

KURU (to come) is also irregular

Common verbs:

IKU (to go)

IRU (to be)

TABERU (to eat)

NOMU (to drink)

HAIRU (to enter)

DERU (to exit [also to attend])

KANGAERU (to think)

MANABU (to learn)

That's a start.