MyBB Community Forums

Alright , i wanna give certain groups , few premissions such as unbanning and banning , editting the forums (Sub Forums) , editting groups Etc..

How can i?
Is there a specific plugin?

IMO, only selected few persons should have such privileges. And in general, they need admin panel access.

Access to different sections in the admin panel can be restricted. see Admin Permissions

i know that and i want to allow admin access to certain users but i want liited access , like only for usergroups and forums & posts , and also bans

You can manage what a usergroup and person can access in the Admin CP under Users & Posts -> Admin Permissions.