Absolutely, there's 2 functional save editors out for the game at the moment.

Apocalyptech's CLI Editor, which has a useable online interface by Abramhindle here

and

Somefunguy's GUI Editor, which is a fork of FromDarkHell's BL3 editor

Somefunguy's editor is going to be a lot more useful to you for editing items.

Note that it takes quite a bit of research to figure out which parts a legitimate item can have, it's really easy to accidentally make illegitimate gear with an editor if you don't know a lot about the item you're trying to make and what parts a valid version of it can possibly have.

Part documentation on this game is currently really incomplete, I might even be the only person working on it. I've been working on my own compiling a list of which parts do what and which items the part can spawn on but it's exhausting work and I am months, at least, away from completion.