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