Bolster rhymes with:
holster, pollster, polster, toalster, upholster, balster, elster, galster, holster, pelster, pollster, polster, toalster, ulster, upholster
Bolster sounds like:
balestra, balestrieri, balistreri, ballester, balster, belcastro, blacketer, blaster, blister, blockader, bluster, blustery