Based on tears, new words formed by adding one letter at the beginning or end:
a - aerst b - reatas c - barest d - baster e - breast f - tabers g - carets h - cartes i - caster k - caters l - crates m - reacts n - recast o - traces p - daters r - derats s - stared t - trades u - treads v - aretes w - easter x - eaters y - reseat z - seater