Pasts rhymes with:
blasts, castes, casts, fasts, forecasts, lambastes, last's, lasts, masts, nast's
Pasts sounds like:
packets, packwood's, pact's, pacts, pagoda's, pagodas, pas-de-deux, pastas, pastes, pastiche, pastiches, pectic, pesetas, pestka, pests, phagocytes, physicists, piaget's, pickets, pickett's, picts, pistachio, pistachios, pockets, posits, post's, post-attack, postage, postdates, posts, psychotic, pussycats