StackMob for 1.16.5+. StackMob 5 uses Bukkit's PersistentDataContainer API so performance will be greatly improved from previous versions.
StackMob is a plugin that reduces the strain of mobs on your server by 'stacking' them together, therefore you can have 1 entity instead of 30 entities. StackMob aims to try and not break vanilla mechanics, however this is not always pratical and/or possible.
It is recommended to use StackMob in conjunction with a farm limiter plugin for the best results.
In order to build StackMob, you will need to do the following.
Contributions are welcome. StackMob is licensed under the GPLv3.
StackMob does have a few custom events that can be used. These are in the events subpackage.
Maven:
<repository>
<id>CodeMC</id>
<url>https://repo.codemc.org/repository/maven-public/</url>
</repository>
<dependency>
<groupId>uk.antiperson.stackmob</groupId>
<artifactId>StackMob</artifactId>
<version>5.8.2</version>
</dependency>