A torrent index that I can view thru an emacs mode would be the most useful. If the data format is just a text tile with each torrent taking one line would be amazing. It would be long, but it's just text so memory consumption is negligible. Kinda same style as Org-mode, I imagine.

You could just search like usual, open a magnet with Return, click 'c' for it's comments. When opening the file, the mode would check for seeders/leechers and display it inline.