Knick-knacks rhymes with:
knacks, snacks, antitax, attacks, ax, axe, backes, backs, bax, black's, blacks, blacks', cac's, caq's, chirac's, cracks, dacs, dax, dax', fax, flax, hacks, haq's, jack's, jacks, jaques, knacks, lac's, lacks, lax, mac's, mack's, macks, macs, max, maxx, neoax, pac's, packs, pacs, pak's, pax, plack's, plaques, plax, pretax, quacks, racks, rax, relax, sachs, sachs', sacks, sacs, saks, sax, saxe, shacks, slacks, smacks, snacks, stac's, stacks, tacks, tax, track's, tracks, trax, ty-sachs, vax, wacks, wax, whacks, yax, zack's, zacks
Knick-knacks sounds like:
kansan's, kansans, kansans', keynesians, knick-knack, knickknack, knickknacks, knocking, kyongsang