Shiny brave weapons

[Goosetave]

Do they even exist ? Only ones i've seen are the ones from the quests.

[Jagdtiger]

About 5% drop rate. Allegedly higher drop rates from higher wave and difficulty drops, as well as from the token chest

[Lil C]-[ew C]-[ew is ☂д☂]

As the first replier comment. Someone else have as well pointed out this as well. So keep playing 50 wave Onslaught ( legend optional ) with focused attune and you will get something. Found this Edge Transit and I still haven't used since I'm enjoying Tarnation.
https://steamcommunity.com/sharedfiles/filedetails/?id=3229785010

[Badger]

Yeah, they exist, but extremely rare, the redeeming thing about them is that you can get them for anywhere basically.

Brave engrams, random challenege completion drop, Onslaught chest...etc, literally anything that can drop a Brave weapon has a chance to drop a shiny.

Best way to farm them I assume is Legend Onslaught, since you get 2 chests per wave set.