The first way would be to put “endorsements” in your profile. Simply stating recommendations on who to follow next.

The second way would be some kind of list. But it’s exposure would require clients or a specific client to create the list for that purpose and read others lists to convey the recommendation. Does listr already do this?

The third way would be a new kind. “Endorsements” or something similar like “recommendations” where npubs post their recommendation note to relays that clients can specify look for and aggregate into recommendations from who you follow. My two sats.