6 verses have
But
in Edition Clear Qur'an by Talal Itani / Al-Hijr (The Rock)

15:11But no messenger came to them, but they ridiculed him.

15:21There is not a thing but with Us are its stores, and We send it down only in precise measure.

15:45But the righteous will be in gardens with springs.

15:56He said, “And who despairs of his Lord’s mercy but the lost?”

15:81We gave them Our revelations, but they turned away from them.

15:83But the Blast struck them in the morning.