Category:Plugins
Plugins are serverside only. A plugin can do a lot of things from adding things to the game to control the server. What a plugin can't do is add extra graphics in form of blocks, mobs, items and so on. Ex. If a plugin would like to add a want to the game it can do that by changing a stick (as an example) as a wand. It would have to use one of the sticks already in the game, but it can make it only function as a wand if it have a special name or a special attribute/tag on it. But it can't add a new stick with a different look (like actually looking like a wand). For that you'd need a mod instead. The pros of using plugins is that you don't need it on the client, only on the server. This make a lot of vanilla servers use plugins to add things to the server (like minigames, special abilities and so on) and players can still join with the vanilla game.