The internet sensation -- who went viral just weeks ago -- inked yet another deal amid her meteoric rise in popularity ... this time, linking up with Leaf Trading Cards for an exclusive series of cardboard collectibles.

The company says fans can buy packs for $100 a pop ... and each batch will feature one autographed card with a unique inscription below a snapshot of her rocking a cowboy hat.

One example of Welch's handwritten phrases reads "I heart Pookie" alongside her Hancock ... a nod to a comment she made in the original video that started it all.

The cards are numbered ... and also feature rare versions scribbled with red and green autographs. Get this -- our folks at Leaf tell TMZ Sports the cards are selling like crazy ... and 75% of the inventory is already gone.

"Haliey has been amazing to work with and is one of the most down-to-earth individuals I've encountered in the sports trading card and celebrity industry," Leaf director of marketing and licensing CJ Breen said.

It's just another example of Welch cashing in on her newfound fame -- as we previously reported, our sources say she received around $30,000 for her first public appearance ... and it's safe to say she also got a pretty penny for attending the Jake Paul fight on Saturday.