It would be great to have a Tab Folder on Opera GX.
It's going to be very helpful if you implement them since you can organize all your tabs. You can have a tab folder for school, a tab folder for gaming, a tab folder for miscellaneous stuff; it could have like a simple code to open the folder if they want to have a code. Like a passcode of 4 numbers to open a folder that may contain private information on the tabs inside of it.
Also the tab folders should have color codings to make it have a better appearance rather than just gray. It would have your browser colors on it or you can customize it the way you like.