So I just did a fresh install of MyBB. I've used it before years ago. I wanted to install some plugins so I uploaded the files but when I go to activate them in my ACP, they don't show up, it's just blank.
Check your PHP error log.
DVZ Shoutbox & MyProfile they are both for 1.8
Can you remove the plugins you have added in plugin folder to see if the plugin page in admin panel is showing or not ?
Most probably a plugin has corrupted your plugin page in Admin Panel.