I just did an internet search on PB & lettuce sandwich and there was a huge number of results, including combinations of PB & L with other ingredients alone or together, e.g. mayo, tomato, bacon, dill pickle or gherkin, etc. One combination called a rainbow sandwich included thin slices of carrot, lettuce, and fresh raspberries. Now that IS weird!

I'm coming to the conclusion that PB is the jack of all trades for sandwiches. It can be combined with sweet or savoury ingredients or a combination of both, kind of like the salted caramel phenomenon.

I think I'll have to set up a spreadsheet to list all the suggested combinations, and add my rankings and comments for each.