Unless the Cowboys are willing to trade La'el Collins for Rishard Mathews (and they aren't), there isn't anything else out there worth pursuing.
Hell, I'd trade Mathews to get back our 3rd rounder at this point. I still think Kenny Stills has the bigger upside and there's no way we can pay FA contracts to Derrick Shelby, Lamar Miller, Rishard Mathews and Olivier Vernon next year (and Vernon isn't worth it, either). Once Devante Parker hits the field he and Stills are your outside threats - with Jarvis Landry and Jordan Cameron pushing the middle and deep seams. There's simply no place for Mathews after this season, even with as well as he's playing now.