I only ever used reverse (idle) on taxi out on the B737-200 with the clamshell reversers (best reversers I have ever used!), usually only ever in the summer on hot days. As an aside, the 737-family was also the only aircraft type with no brake temp display that I have flown.
At one point on the B737-200 the manuals did permit reversing back from stand, and it was practised in the sim, although never used in reality at BA.
As Finncapt says, taxying out at Stuttgart for Runway 25 was a challenge in summer in the early A320's at BA without the brake fans, although I never had to resort to using reverse, as far as I can recall.