Hi Nekka, although they are not credit cards, store loyalty cards tend to offer a lot of cashback. The Boots Advantage Card is my favourite. You earn points each time you shop, and you can redeem these points at your next visit. I shop at Boots a lot, so I get many reward points. Sometimes, I buy cosmetics with just my reward points. It’s even better if you are a student - you get a student discount in addition to loyalty points.
Barclays also offers cashback on several retailers in the mobile app. It’s worth checking out if you have the Barclays app.