Answer:

AEIOU

Answer	Crossword Clue
AEIOU	Vowel sequence
AEIOU	Familiar quintet
AEIOU	Alphabetical quintet

AEIOU	Quintet seen in late-night hours?
AEIOU	Grade school quintet
AEIOU	Sequence that may end in "y"
AEIOU	Vowel quintet
AEIOU	Alphabetical sequence
AEIOU	Basic quintet
AEIOU	Series that may end in "y"
AEIOU	"Wheel of Fortune" purchase options

AEIOU	Elementary fivesome
AEIOU	Facetious quintet?
AEIOU	Elementary sequence
AEIOU	Familiar fivesome
AEIOU	Group with a Y, sometimes
AEIOU	Sequence with a Y, sometimes
AEIOU	Alphabet quintet
AEIOU	Grammar school sequence

AEIOU	Second-grade sequence
AEIOU	Abecedarian's group
AEIOU	"... and sometimes..."
AEIOU	Low-count Scrabble quintet
AEIOU	"... and sometimes Y"
AEIOU	Alphabetic quintet
AEIOU	Sesame Street quintet
AEIOU	Sequence sometimes ending in "y"

AEIOU	Vowel group
AEIOU	Facetious, half-serious, abstemious quintet?
AEIOU	"Wheel of Fortune" purchase choices
AEIOU	Letters before "and sometimes Y"
AEIOU	"Wheel of Fortune" purchases
AEIOU	Purchase options from Pat Sajak
AEIOU	Elementary quintet
AEIOU	Five of a kind, alphabetically

AEIOU	Facetious fivesome?
AEIOU	Abstemious quintet?
AEIOU	Phonics lesson quintet
AEIOU	Things purchased from Pat Sajak
AEIOU	Kindergarten quintet