We accidentally bought two packs rather than just the one on our last shopping trip and I've sated myself with the usual butter / jam / peanut butter options.
I'm a bit of a crumpet purist. Only butter will do for me. All these other things mentioned are things I would contemplate on a toasted muffin, but not a crumpet.
I'd just chuck the other pack in the freezer until I fancied another crumpet or six.
I'm another one who loves grilled cheese. Also (maybe this is me being a weirdo) I love butter, apricot or strawberry jam with sliced mature cheddar cheese on top...hmm.
I make mini pizzas with crumpets. A shop bought pizza topping, salami, sweetcorn and melty cheese, shove 'em under the grill until bubbling. I defy anyone to just eat one! ?