StopForumSpam
Plugin
Official
Block known spammers at registration and report new ones.
Checks every registration against StopForumSpam's database of known spammer usernames, email addresses and IP addresses. A match at or above the configured confidence score is rejected, and the attempt is logged for admins to review.
Members who are allowed to ban users also get a "Report spammer" button on profiles. It reports the account to StopForumSpam and can ban it at the same time. Reporting needs a StopForumSpam API key.
After installing, run the migrations with flaskbb db upgrade.