Dunno about the supermarket cards but I have a set of cards that I bought by mail order in the early 80s, one of these partwork things where you get another set each month on approval and pay for them if you like them. Fills 3 fat ringbinders and has been invaluable throughout my cooking life.
Also have a ringbinder full of various ripped-out-of-magazines recipes that have taken my fancy from about 1985-present.
Have a version of Jamie O's first book that was doing the rounds as a freebie on the net a few years ago, use that a fair bit.
An ex-library-book of veggie recipes by a woman called Janet Hunt, some good ideas in there.
Also the Good Housekeeping Book of Chocolate is well-used!
I've a couple of other Good Housekeepings that I use occasionally too, their Chinese isn't actually too bad!
Don't really have any bad ones, if I don't like them or don't use them I tend to give them away. Never got on with Delia, or Nigella, and wouldn't gibve either of them shelf-room again.