Is there any plugin for restrict number of successful frontend logins per user? I looked around but without success, and have no idea how to achieve that on the other way. Any advice? Joomla is 3.8.1
if "restrict number of successful frontend logins per user" is one per user, then Login One! might be what you want.
If you need more logins >1 then you 'll probably need the Business edition
The plugin Login Limiter will do the job. https://www.innato.nl/index.php?option=com_content&view=article&id=17&catid=11&Itemid=121#plugin_login_limiter_j30