There's been a few over the years for me, when I used to log every bus I travelled on, you could see which vehicles would always appear (though some were on purpose like Olympians etc). But I do recall getting on Tridents 3862 and 3865 a lot, whilst with the Lance SLFs I always tended to get 4772 when I was younger.

Stagecoach wise, that B7TL they had on long term loan in the early 2000s cropped up a few times.

Arriva it tended to be MetroRider 883, Olympian 7293 (prob more on purpose), Scania L113s 271/272.

As for independents....
Compass Travel, I used to end up on the Hairy Lemon a lot (E734WEC), and same went for it's previous operator Amberline. (https://www.flickr.com/photos/tcd481j/48907664563)

Classic DAR123T appeared a lot for me, again prob on purpose.

Henry Coopers, Leopard TBR527V appeared a lot, though that was mainly because it was allocated to my school bus.


Elsewhere, one holiday in the Ayrshire Coast, I kept getting on Volvo B10B M151FGB of Stagecoach West Scotland. (https://www.flickr.com/photos/gjm-photog...7495858020)