i am by no means a speedrunner, but while playing the game i kept thinking about this type of category

it would specifically be trying to get the fastest time with the fewest unique echoes learned, i.e. if you only ever learn the table, box, and spear moblin, that would be 3 total echoes learned.

there are somewhat similar categories in other games (odyssey has a fewest captures extension which is somewhat similar), and i think this type of run could be really unique here to optimize which echoes are the most versatile!