In John Kavanagh's point of view, though, there is one name that stands out above all the others.
McGregor's coach would prefer to see McGregor remain at lightweight, where he is now UFC champion, and face Diaz next.
"I understand Khabib is the No. 1 contender and it's probably gonna be him if that's how the company works," Kavanagh told Ariel Helwani on Monday's edition of The MMA Hour. "But for me, interest wise, the Nate fight would interest me greater because of that. If it's Tony, if it's Khabib, great. They're both fantastic fighters."
McGregor beat Diaz by majority decision back in a rematch in August at UFC 202. Before that, Diaz defeated McGregor by second-round submission. Both fights took place at welterweight. This one, if it happened, would logically be at lightweight for McGregor's belt.
McGregor vs. Diaz 3 would likely be the biggest fight from a financial perspective available to McGregor next. It's not just that, though. For Kavanagh, Diaz is also simply on a higher level than the others.
"I think the second-best 145er is Max Holloway," Kavanagh said. "That's my opinion. And I think the second-best 155er is Nate Diaz. I think Nate would beat either Tony or Khabib. I think he really turned the corner with the Michael Johnson fight. I think we saw a new version of him. And then he looked fantastic in both Conor fights."
Diaz has never fought Ferguson or Nurmagomedov, who are higher in the rankings than him. Diaz does have a loss to Rafael dos Anjos, who has been beaten by Nurmagomedov, Ferguson and Eddie Alvarez, the man McGregor defeated to win the 155-pound belt Saturday at Madison Square Garden.
On that same UFC 205 card, Nurmagomedov dominated Johnson, eventually beating him by third-round submission. Afterward, he called out McGregor, called him a "chicken," and essentially challenged the entire country of Ireland in a fantastic promo.
Kavanagh heard it and also saw Nurmagomedov's performance. It was the early part of that bout against Johnson that the coach took particular notice of. Johnson connected a few times to Nurmagomedov's chin.
"In the first two or three minutes of the Johnson fight, we kind of saw what would happen if he was to face Conor," Kavanagh said. "He got tagged quite a bit. I just think that sort of power and accuracy Conor brings, I'm sure Eddie had a great plan until 60 seconds in when he was scrambled. I don't think it would go massively different if he was to face [Nurmagomedov]. Tony gets hit a lot as well. Super tough guy. Keeps coming forward. Tough fighter. I think it would go that way."
Many people would disagree with Kavanagh's assessment. McGregor hasn't faced a wrestler of Nurmagomedov's caliber, pundits will say. Kavanagh is fine with that. He thinks if people stop finding potential challenges for McGregor, all the fun will be lost. He wants the "intrigue."
That intrigue, though, begins for him with Diaz and that trilogy fight. After the second go-around, many people were calling for a third fight. That was before McGregor held two belts at once. Now he has the lightweight and featherweight straps. The hardcore fans will piss and moan if he doesn't defend against the arbitrary No. 1 contender. That is not important to Kavanagh.
"I do think Nate would, not comfortably, but [he would] be quite a bit better than either of them," Kavanagh said, referring to Nurmagomedov and Ferguson. "If I had the magic buttons to press as a fan, [McGregor vs. Diaz 3 is] the fight that would interest me the most."