Here is the Blacklisted plugins for WordPress and are considered not safe for installation over your web or blog. The back listed plugins are divided as per the categories includes: Backups, Caching, Unnecessary / nonfunctional, Stats, Duplicate functionality, Related posts, Security issues and Performance.
It is always recommended to use the backup functionality of your web servers, here are the plugins which you should avoid using over WordPress:
Avoid using the following cache plugins:
However, if your site is slow, try using the P3 Profiler plugin to check if your plugins are slowing down your site.
Unnecessary / nonfunctional
These plugins don’t add any value and may not work correctly on our system so it is better to remove them or not use them:
It is recommended not to use the following stats plugins as they tend to have performance related issues and they negatively impact your websites’ performance because they send many requests to your database and can prevent site caching.
These plugins increase database load by using inefficient queries, poor caching, or poor scaling on large sites.
These plugins don’t perform well, in general, especially on large sites.
If you are using one of such plugins, try look for alternatives.