Just came across this deal.
For every £2 you spend using contactless on travel (underground, overground, busses....) Amex will give you 10 extra points.
I use my Amex anyway so seemed like a really good offer!
I only have 1 Amex card so I couldn't check if it was on multiple cards. But it does say 'first 50,000' people so I assume it will be on yours too...just be fast!