こんなのあります

https://relayguardian.com/ nostr:npub1s02jksmr6tgmcksf3hnmue7pyzlm0sxwarh7lk8tdeprw2hjg6ysp7fxtw

> Free users are limited to 5 relay monitors, a minimum interval of 5 minutes, and only can view connection latency.

https://relayguardian.com/pricing