Filed from 2 published puzzles

QRST

Set to 2 different clues across 2 published puzzles, most often “Alphabet run” — The New York Times, Saturday, 8 July 2006.

4 letters

Every clue on record, most used first

Alphabet runonce
The New York Times — Saturday, 8 July 2006
Alphabet quartetonce
The New York Times — Friday, 16 October 1998

Other answers to these clues

CDEF4 letters
LMN3 letters
LMNO4 letters
MNOP4 letters
RST3 letters
RSTU4 letters
STUV4 letters