Here's what rhymes with ubbubboo.
to do two too due du dew tu chew deux adieu ado bu ju jus peu pu boo chou chu doo tue pooh poo who you new true knew blue drew u blew coup qu shoe zu anew lieu shew su sue undue vous fu lu rue stew taboo undo zoo brew hu ku loo mu nu pew seu shu sou tattoo vu woo yew yu coo cou ewe feu gu ru shou thu tzu vou wou wu goo moo shoo gnu roux thew whew booboo into through few view grew que crew pursue threw flew q avenue bamboo canoe clue cue glue hue queue accrue cu debut flue slew subdue untrue flu jusqu piu thru beaucoup eschew fue hew mieux outdo shrew sprue vnto vue clew mew redo strew cockatoo halloo spew valuer bugaboo zebu kazoo peekaboo slue phew achoo residue screw renew ensue retinue overdue skew shampoo askew imbue outgrew overdo ballyhoo honeydew endue indue marabou bestrew buckaroo wazoo regrew atishoo review revenue hitherto withdrew rendezvous caribou construe barbecue kangaroo revue sinew hullabaloo barbeque fondue foreknew muumuu overshoe prevue overdrew interview overview overthrew overflew superglue overgrew misconstrue