Here's what rhymes with undergo.
go ago co goe ko no so know though low show grow row tho fo foe glow ho lo quo bo doe dough mo po ro toe wo woe crow indigo tow yo beau ceux faut hoe jo sew soe uno vo aglow beaux cho dau dicho mow noe roe sho yeux zo dunno rho tarot turbot undertow whoa doh kayo pekoe below flow blow slow snow throw pro plateau fro chateau hello thro bio propos tableau aliquot floe medico tableaux topos tuo afterglow bro chateaux plateaux stow throe trow kapok sloe gateau pompano gateaux borzoi schmo schmoe although embryo audio bestow buffalo patio portico bungalow calico dynamo forego forgo nouveau polio vertigo apropos cameo domino escrow outgrow siglo trousseau chapeau oleo piccolo deathblow overgrow regrow bandeau matzoh chapeaux trousseaux resew ratio radio overthrow studio overflow folio stereo politico mistletoe rodeo spatio adagio foreknow fatso romeo tallyho archipelago oregano pistachio mustachio microdot moustachio presidio pianissimo portfolio impresario braggadocio generalissimo