This is a list of English auxiliary verbs, i.e. helping verbs, which include Modal verbs and Semi-modal verbs. See also auxiliary verbs, light verbs, and catenative verbs.
Primary Auxiliary Verbs
be
do
have
Single Word Modal Auxiliary Verbs
best better can could dare
may might must need ought
shall should will would
Two Word Semi-Modal Auxiliary Verb Phrases
be to dare to got to (gotta) have to
had best had better need to
ought to (oughta) would rather used to
Three Word Semi-Modal Auxiliary Verb Phrases
be able to be about to be allowed to be bound to be forced to
be free to be going to (be gonna) be likely to be obliged to be required to
be supposed to be unlikely to be used to get used to have got to