General Requirements + Tips
To hack your 3DS/ XL/ 2DS with any of the following, you must have the software version 9.x up to 9.5.0-22. If you have updated to 9.5.0-23 or higher, you will not be able to use these hacks, no exceptions. The creators of all the hacks have stated there is absolutely no way around this yet.
These hacks can be used on both physical and digital copies of New Leaf. It doesn’t matter how many copies you have; you can hack them all!
The number one thing you have to do before using any of these hacks is to back up your save file, explained in steps 1- 7 here. LeafTools also provides a way to back up your save file, but I recommend the one I link to, because that will also be the save file both the RAM editor and map editor use to edit your town. By backing up your save file, you guarantee that your game can be restored if it happens to corrupt from hacking.
LeafTools Hacks
Things you can do with LeafTools:
Backup/ restore multiple save files
Water flowers, unbury items, pull weeds
Max out your bank account
Max out your island medals
Fill your town with/ remove all grass
Unlock all Public Works Projects
Unbox a moving villager
Rig the stalk market
Duplicate items
Move out an unwanted villager
Remove/ add rocks
Put a train station locker in a house
Generate items*
Create, move, or destroy buildings*