Signature Magical Item
I love magic items! Classes only get you so far in D&D so much power and creativity is handed to players when you give them a magic item. So many insane stories come from players using a magic item in a way the DM didn't imagine. One of the greatest of all times has to be Jester offering a Hag a cupcake.
While I will give you access to many magical items throughout the course of the campaign I like to give players a magical item that grows with them. This does two things. First its another way for you to direct your character's narrative and second it gives me as the DM a parallel way to offer character power advancement without just leveling you up.
There is no cap on how strong these can get. By the end you can be rocking a Artifact that you designed throughout the whole campaign. However at the until you are level three they cannot give a flat +1, +2, or +3.
If you want a starting point for your magic item check this. pretty much everything in there (except the +1 gear) is fine to start and we an rework your magic item over time if you aren't happy with it.