I'd be looking at some of the players I liked as rookies who haven't been given an extended opportunity yet.
MarShawn Lloyd might have been my favorite rookie RB this year, but injuries have made him irrelevant. I'd be testing his owners with trade offers right about now. It's a move that might win you a league in the future because his ceiling is off the charts if he puts the pieces together.
Javon Baker has been invisible in New England so far. I liked him as a draft prospect. I also liked Boutte last year and he barely played as a rookie. This year he has been a lot more involved. It doesn't always happen right away. I'd be holding/buying Baker and hoping he can have a good camp next summer. New England's WR depth chart is jammed with a bunch of medium-good guys like Polk, Bourne, Boutte, and Baker. At the moment none are very relevant, but that can change.
Jermaine Burton is another rookie WR headcase who has the talent to impact in the future.
Not sure if anyone is holding AJ Barner in dynasty leagues, but there's a Kyle Rudolph type of ceiling there. Pretty decent rookie year so far. Theo Johnson was also showing flashes before his injury. The upside of these TEs is not exciting, but they can be bye week cover with medium long-term potential.
If we're talking about veterans, I still don't think we've seen what Alec Pierce looks like with capable QB play. He'll be entering the final season of his contract next summer, and his skill set seems like it may attract FA interest. Teams want big plays and deep threats. Gabe Davis got a nice contract from Jacksonville and he's a fraction of the player Pierce can be. If you stick Pierce with an elite downfield passing QB, he becomes a realistic 1,000 yard threat weekly starter type of guy IMO. Even with horrendous QB play and spotty target volume, he is 31st in the NFL in receiving yards.