TerraInveditThreedee 3DS

Confusing "UI"
Has a weird text-based interface
You can hack in items that aren't existing in the game's code
Can edit your coin pouch and your ammo case too
Very fast and responsive
Supports dynamic savadata opening (even if installed on NAND / gamecart (for goatwait users))
Somewhat colorful

Not intended "features":

The code is not checking if the current modifier could be applied for the current item, so Terraria will "correct" it to a different, and often worse modifier
Trying to delete your edited player file from Terraria crashes, and reboots the system, but it deletes the player file anyways

Note: Developer items disappear after a while, and you can't equip them. But you can equip Red's wings, and that one doesn't disappear.

Thanks to @HappyzLife for the application icon!

If you don't know how to run the downloaded file, take a look here: https://smealum.github.io/3ds/