Hi Gary
Off the top of my head - Sherman Firefly, Centurion Mk I, Comet (called 77mm, but same round with thicker driving band, shorter cartridge), Archer SPG, Charioteer, and may be some one offs.
Checked Wiki - https://en.wikipedia.org/wiki/Ordnance_QF_17-pounder - forgot Achilles - a TD & mixed up Challenger with Charioteer (the latter had the 20pdr)

Mal