How to create more plugins using Theia plugin for Eclipse che

I was creating some plugins for my Eclipse che IDE, i have already created few plugins but i would like to know how far i can go with this Theia plugin APIs because Theia plugin APIs seems that they are only useful for simple tasks only

[original thread by tomevision]

[Anatoliy Bazko]

You are able to create the same kind of plugin like existed VS Code extensions.
Here is the list of supporting VS Code API in Theia IDE: