Luckily, there are too many to count. But I'll contribute a few:

I wish I could remember the name of the café, but in Pisa, Italy, I had a great roasted aubergine (eggplant) and buffalo mozzarella panini, alongside a San Pellegrino Aranciata. I'd like to give an extra off-topic thanks to the readily available mascarpone and nectarines from that time...

The mujaddara sandwich from Kalustyan's in Manhattan, New York. Lentils, onions and groats, with a side of pickles - well done indeed.

Broccoli rabe, provolone and roast pork at Tommy DiNic's in Philadelphia. Ate it a few days ago, should've been sooner than that.

Many varieties of Yamazaki pan (bread) in Japan. Peanut butter, maple syrup and margarine (uhh), katsu, to name but three. Never refrigerated, keeping it classy.

Pretty much any sandwich I've come across in the Levant is worthy of this reply.