I can’t come up with just one and this list changes over time a lot for me. But here is a current top 3 for me

Dry the River - Weights and Measures

Tallest Man on Earth - Dark Bird is Home

Elbow - One Day Like This

I think what would be interesting is to get everyone who self hosts this do part of the indexing. As in, find some way to split the indexing over self-hosted instances running this search engine. Then make sure “the internet” is divided somewhat reasonably. Kind of what crypto does, but instead producing the indexes instead of nothing.

“Currents” is pretty good if you like metalcore!