Extentions:
https://chromewebstore.google.com/detail/flamingo-%E2%80%93-nostr-extensio/alkiaengfedemppafkallgifcmkldohe
https://chromewebstore.google.com/detail/nos2x/kpgefcfmnafjgpblomihpgmejjdanjjp
https://chromewebstore.google.com/detail/aka-profiles/ncmflpbbagcnakkolfpcpogheckolnad
https://keys.band/
https://github.com/haorendashu/nowser
https://chromewebstore.google.com/detail/gooti-nostr-identity-mana/cpcnmacmpalecmijkbcajanpdlcgjpgj
Deskstop Bunker Signer:
https://github.com/nogringo/peridot?tab=readme-ov-file
The Remote Signer:
https://nsec.app/
https://github.com/kind-0/nsecbunkerd
Native Android Signer:
https://github.com/greenart7c3/amber
iOS
https://testflight.apple.com/join/8TFMZbMs
https://testflight.apple.com/join/DUzVMDMK
https://testflight.apple.com/join/qgkAMPgU
Higher Security Options: To start using Nostr with secure, revokable key shards: https://nstart.me/en
For Existing Keys: https://www.frostr.org/
Thank you to https://nostr.net/ for keeping a thorough list of Nostr apps, clients, and tools!