Anything made by shunyata, generally, anything “cryo-treated” and specifically speaking, “audiophile fuses”, absurdity increasing geometrically with price.
What’s your vote for the most ridiculous, overpriced, and useless tweak?
My vote: Furutech Outlet Cover 105 NCF $220, with “special crystalline material that has two “active” properties.” https://www.thecableco.com/outlet-cover-105-ncf.html