So this is RedBird1578, a DeviantArt user who has been stealing scratch vectors for a while. Here are some examples:

Here's DakimNewacc's old Effed Up Fids vectors on some art for Gangam Style

Recreation of a scene in The Angry Birds Movie 2 with stolen vectors of Leonard, Courtney and Garry

Lots of stolen stuff here. I can't mainly spot vectors by DakimNewacc and TheWorldofAZ.

ferges' vector of Gordon attacking Pico from Pico's School

My old George vector next to George Washington

You get the point by now

Basically everything here is a stolen scratch sprite.

Now, I have a theory (A bird theory) that this guy either works on or found the sprites from the Angry Birds Fanon Wiki, which has stolen a bunch of scratch vectors too.

The reasons on why I think he could work on this wiki are:

His OC has a page on the site (or maybe he stole the oc too, idk)

The site stole all of DakimNewacc's vectors of the stella gang, expect of Dahlia. RedBird1578's art does the same.

However he also has stolen vectors that arnt on this site, like Gordon and Dusk. I am not 100% sure that he works on the site at all, but it's kinda suspicious that there's some parallels.

That's all for now, thank you for reading.