Here is a list of verbs that start with CU.
cubed, culminate, culminated, culminates, culminating
cultivate, cultivated, cultivates, cultivating, cultured
cumulate, cup, cupped, curb, curbing
curdling, cure, cured, curing, curl
curled, curling, curse, cursed, cursing
curtail, curtailed, curtseyed, curved, curving
cushion, cushioning, cut, cuts, cutting
Hope you enjoy this page of verbs that start with cu and the rest of this verb list site as well.
Did I miss any verbs? Visitors can make this a more useful online resource by listing more verbs in the comments.