Include memcache and settings for ram etc as standard.
Since Plesk Onyx you will be able to install memcache as a Docker container and configure http(s) proxy rule for it to map to your web app.
Docker and proxy rules are available in Plesk Onyx Preview already, you can try it here https://talk.plesk.com/threads/plesk-onyx-preview-and-feedback.337172/
include php-memcache(d) extension in php plesk pack
Madalin Ignisca commented
APC can be added easy by any sysadmin.
Redis would be a lot better then Memcache as it supports PASSWORDS for each instance.
This way an instance could be attached to a subscription with a random password provided to the client only.
A mention is that passwords can be discovered by clients with full ssh access from the configs. It can be fixed by changing permissions to the folder and files for Redis configs.
I give a vote so the Plesk stuff would consider Redis or Memcache with sockets (like php-fpm) instead of tcp ports (personally I can secure Memcache as well in other ways).
Manuel Rios commented
Include MEMcached as a module instalable on plesk options
Benjamin Hodgetts commented
This should ideally be "Memcached" rather than "Memcache" which is the older, not as feature rich version. It's one of the few modules missing from the "Multiple PHP Install" packages which is a major problem for some people.
apc is redundant due to opcache in php
Kerem Şen commented
Plesk should have Memcache and APC
Plesk should have a caching section, with controls for PHP opcache, Memcache and redis.
this is super idea :)