Book, brook, cook, crook, hook, look, rook, shook, took, mistook, undertook, forsook, stook,* betook.
OOL.
Cool, fool, pool, school, stool, tool, befool, spool,† buhl,|| pule, rule.
OOM.
Gloom, groom, loom, room, spoom,† bloom, doom, tomb, entomb, whom, womb, plume, spume, etc.
OON, see UNE.
Boon, soon, moon, noon, spoon, swoon, buffoon, lampoon, poltroon, tune, prune, coon,§ June, hewn, dune,* shalloon, dragoon.
OOP.
Loop, poop, scoop, stoop, troop, droop, whoop, coop, hoop, soup, group, dupe.
OOR.