Categories: Antispam Plugins, Downloadable Plugin, 6.x
This plugin allows you to add proof of work CAPTCHAs to your site in the form of a checkbox verification.
Category: "Antispam Plugins"
Categories: Antispam Plugins, 2.x & above, 3.x (incomplete list), 4.x (incomplete list), 5.x, Bundled plugin, 6.x, 7.x
The Basic Antispam Plugin provides basic antispam features like: allow anonymous comments, detect feedback duplicates, feedback sensitivity to links, apply rel="nofollow", block spam referrers, check referrers for URL and check trackbacks for our URL.
Categories: Antispam Plugins, Bundled plugin, 6.x, 7.x
This plugin allows you to add CAPTCHAs to your site in the form of simple questions requiring simple text answers.
For example the site would ask "What animal is Bugs Bunny?" and the user would need to type in "rabbit" or "a rabbit".
Categories: Other Plugins, Antispam Plugins, 5.x, Bundled plugin, 6.x, 7.x
This plugin allows you to use the GeoLite2 database from MaxMind to determine in which country users are located in.
Categories: Antispam Plugins, 1.8+, 5.x, Downloadable Plugin
This plugin allows you to use SpamAssassin to get Spam karma for comments.