This command adds 16 new potions (use existing effects) It works in a complicated way so let me explain... When you activate the command you get a sign called 'All Potions'. Place this down and then click it, and it will give you four more signs. These should be called 'OP potions','Bad Potions','Good Potions' and 'Misc Potions'. Each of these signs will give you four potions. The reason I did it this way was because each sign can only do four commands. If you are using 1.10.2 they should come up with the right textures.