Or search: bettering, meliorative, ameliorative
4 Syllables: SUUU
decorating, generating, liberating, moderating, operating, separating, tolerating
5 Syllables: USUUU
accelerating, collaborating, commemorating, cooperating, degenerating, deliberating, deteriorating, elaborating, enumerating, evaporating, exaggerating, exasperating, exhilarating, inaugurating, incorporating, invigorating, obliterating, regenerating, reiterating

Found 26 words across 2 groupings.