Hello 
What are the most important plugins that do not affect the speed of the site?
in theme ( Epsilon Osclass Theme )
Because there are add-ons built into the theme
So I asked before buying
Please advise
thank you 

The SEO plugin should be required, preferably the Backoffice Manager plugin, and all this does not make sense without the Osclass Pay plugin.

The SEO plugin should be required, preferably the Backoffice Manager plugin, and all this does not make sense without the Osclass Pay plugin.

thank you for replying
What do I mean by these additions, are they necessary with the theme?

Infinite Scroll Osclass Plugin
WebP Images Generator Plugin
PWA Osclass Plugin
Instant Messenger Plugin
User Rating PluginOsclass plugin
Favorite Items Plugin
Business Profile Osclass Plugin
Exchange Rate MultiCurrency Plugin
Cache Osclass Plugin
StreetMaps Osclass Plugin

Of course, adding what you mentioned earlier

thank you

I am not aware of any plugin impacting site speed, it just add new stylesheet/js but speed itself should not be touched

it's all up to you. You can also add blog or article plugins in the same way