(This was inspired by a fanfic on AO3 that I can't remember the name of, and it's where I got the potato plot point from if I do ever stumble across the fic again, I'll give the name and author so that I can properly credit them.)
Immortal! Techno and Philza AU (?)
Far, far into the future, after L'manburg and the Dream SMP have long given way to history, Techno and Phil still reside in the frozen tundra. They are not alone, however, and are accompanied by a descendant(s) of the Dream SMP members (can be OC or otherwise). One day, (one of) their guest(s) reminisces on a time when Techno had thrown up at the simple sight of a potato. They had known he hated them, but they didn't think he hated them 𝘵𝘩𝘢𝘵 much. They had to know why. What they didn't expect was Techno telling them about the death of his brother.
(Basically, the concept was that after Tommy got beaten to death with a potato, Techno couldn't handle growing them or eating them anymore, and gets physically sick from even looking at them)
Art by winter-mornings on Tumblr