So here is my idea. An enchantment that, when applied to a tool, makes any xp obtained via use of this item more plentiful. I know, how original. However, there are two features that I feel would set this idea apart from all the other xp enchantment ideas:

In addition to making mining and killing monsters yield more xp, it will also cause other activities to yield xp. One such activity would be farming, which would yield small amounts of xp. The other activity which would yield xp thanks to this enchantment would be chopping down trees. It would only affect wood that was spawned by a tree growing or through natural generation of a tree.

Now you might be thinking "this sounds pretty OP" you would be right. It does sound op. This is where the other bonus feature comes in. The overuse feature. This would encourage a player to get a variety of xp sources. Basically, it would make it so the more you get xp from one source using any tool with this enchantment, the less xp you will get in the future. This would be a value on the player, not the tool. So if you keep killing zombies, the zombies will drop less xp. In order to revert this, you have to get xp from other sources using this enchantment. So if you killed so much zombies that you are barely getting any xp, you should try killing some skeletons or mining or any other way to get xp other than killing zombies. You reset it by getting xp. The more xp sources you use, the more xp you will get.

This enchantment could be a double edged sword. It could get you way more exp than you could get normally, but if you use it too much, you would end up getting a fraction of what you would be getting otherwise. There would probably be 3 levels for this enchantment. Each level would raise the max exp it could get(the unused state of the item). For example, at level one, you could kill, let's say 30 endermen before you are getting the same amount of xp you would be getting without the enchantment, but at level 3, you could kill 40 before you are getting the normal amount of xp.

Let me know if this makes sense or if you have any suggestions. Thanks for reading