Jul 1
Add validation for the comment form against spam (forbidden words)
I even made a feature request about this for the WordPress core https://core.trac.wordpress.org/ticket/62703
The essence of the proposal (for theme):
Make a simple textarea field in the theme (there are now similar ones for search: Popular requests and Synonyms), where you can write something in each line, if detected the form will not be sent, but a phrase will be written that the comment contains prohibited text.
WordPress itself has a field Prohibited keywords in comments, which works on a similar principle to the one I described, but it only affects the fact that comments end up in the trash folder (i.e. they are skipped), and for many sites a solution is needed to not accept such comments at all.
This is a simple solution that will save most sites from spam in comments (for example, you can specify: http, @, .com, .net, .org, .php, etc.)
Pending