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