Trio-quartet combos

• If Snow White's dwarfs formed a band, and others
• Rhyme royals
• Groups of seven
• The Pleiades, et al
• Harry Potter novels et al
• Some Dixieland bands
• Deadly sins and hills of Rome, e.g
• Literary gables and others

Wiktionary Word definitions in Wiktionary
n. (plural of septet English)