Floyd Mayweather vs Erislandy Lara at 154: Mayweather is talking about fighting either Khan or Maidana, but Lara is the guy with the size and skills to give Mayweather the toughest fight. Unfortunately, he's the highest risk/lowest reward opponent possible as well. I'd be shocked if this compelling fight ever happened. Lara could improve his chances by continuing to win; a fight (and win) with Canelo Alvarez would probably punch his ticket.
Lucas Matthysse vs Ruslan Provodnikov at 140: Fight of the year potential, knockout of the year potential. Two of the most feared guys in boxing, some of the biggest power punchers in boxing, in the same division, and their promotional differences will almost certainly prevent this fight from ever happening. Shame, as this fight would be guaranteed to be an extremely entertaining massacre, one way or the other.
Guillermo Rigondeaux vs Vasyl Lomachenko at 126: This is a long term fight to watch. We still have to see if Lomachenko can beat Salido, which would validate this potential fight. These are two of the top 5 amateur boxers of all time, one that went 396-1, one went a purported 400-12. A fight between the two would be at a technical level rarely seen. This one could eventually happen, but a lot of things would to line up correctly for it to be an option.