Lymphoblast rhymes with:
blast, blast, classed, glassed, last, aghast, amassed, assed, ast, bast, blast, cast, caste, classed, fast, gassed, gast, glassed, grassed, harassed, hast, kast, lambaste, last, massed, mast, miscast, nast, passed, past, precast, rast, recast, surpassed, unsurpassed, vast