I like this thread! Here are mine:
Pride: Jon Jones. The p4p GOAT who truly believes that he's God's gift to man. Incapable of admitting to wrong-doing or shortcomings on his part. Has allowed his pride to ruin much of his life outside the Octogon.
Wrath: Palhares. This guy has a reputation for continuously attacking his opponents after they tap, and even while a referee is trying to pull him away. Pretty sadistic, so I consider that wrathful
Sloth: pre-Till Masvidal. Many look at Masvidal as the exciting finishing machine, but prior to that, he had a bad reputation for allowing easy victories to escape his grasp. Someone who isn't doing enough to pursue the finish is arguably slothful. That's a stretch, but it's hard to find an MMA fighter that embodies sloth.
Gluttony: Roy Nelson. Obvious reasons.
Greed: Connor. All he's ever been motivated by is more money and accolades (and accolades=money if you think about it). Never even attempted to defend a title or give a guy a chance to make their name off him. Pretty greedy if you think about it.
Envy: Either Diaz brother. It pains me to say this about them because I'm a big Diaz broothers fan. But, much of what they say during interviews or press conferences can be interpreted as being envious. Nick had it with GSP and Nate had it with Connor.
Lust: Luke Rockhold. He's been pretty straight-forward about his affinity for the ladies. Nothing wrong with it as far as I care, but he's the only fighter that comes to mind about embodying this sin.