Programs that run all small programs in parallel and pick the winner: https://blog.computationalcomplexity.org/2018/10/if-pnp-then-we-have-alg-for-sat.html

This idea gives the long-known but counterintuitive result that there is an already-known algorithm that, if P=NP, solves all solvable instances of satisfiability in polynomial time. Gasarch gives a nice roundup of explanatory links in this new blog post.