Here's what rhymes with postmodify.
high thy vi hi modify shy sigh fi hy thigh vie psi hai cy fy sy thei phi by my why die lie y buy fly sky guy tie bi bye chi defy dye nigh pi pie spy thai certify dei fry ly notify quae rye sly ty wir awry lye mai muy nai nullify ratify wry kai lai luy mei tai wai edify mollify sty bonsai deify ossify stratify stye turfy mummify beatify slier apply dry try cry deny justify satisfy testify butterfly gratify ply underlie alibi amplify magnify pacify pry tri trie belie pri terrify typify untie codify mortify ramify aquae mystify spry stultify amebae horrify lanai prettify speechify banzais dandify yuppify supply identify thereby occupy rely hereby multiply qualify specify alkali classify simplify verify glorify purify diversify fortify rectify unify beautify decry falsify lullaby pupae solidify amoebae descry dignify overlie personify acidify demystify firefly ultrahigh blowfly calcify emulsify petrify stupefy dissatisfy overfly scurfy versify barfly hyperbolae shanghai vitrify overbuy reply imply nearby stimuli whereby clarify comply nuclei signify goodbye quantify alveoli samurai standby disqualify termini crucify liquefy objectify vilify detoxify dragonfly retry triply vivify misapply reunify liquify scarify declassify drachmai gentrify ripply syllabify exemplify intensify indemnify oversupply resupply electrify preoccupy misidentify refortify solemnify oversimplify reclassify revivify transmogrify cumuli