Catalyst rhymes with:
capitalist, gentlest, littlest, agriculturalist, analyst, beautifullest, capitalist, conversationalist, evangelist, formalist, gentlest, herbalist, humblest, institutionalist, journalist, littlest, monopolist, nationalist, naturalist, neutralist, novelist, panelist, photojournalist, populist, psychoanalyst, socialist, specialist, stablest, televangelist, ultranationalist
Catalyst sounds like:
cataloged, catalogued, catalyzed, costliest