The only ones I would say with confidence are:
1. Pop
2. Doc
It's weird, I was talking to my buddy about Spoelstra the other day. Normally our main metric for evaluating coaches (moreso than players) is their ability to take teams deep into the playoffs/to the finals/to win a championship. We can watch players and glean quite a bit more about them than we can about what a coach says and does day in and day out.
And yet, Spoelstra is a weird case. Immediately when he became a head coach, he found himself in a situation where he was completely loaded with three of the most talented players in the league, and a complement of role players. He's been to the finals every year (I think?) and won it twice, maybe a third time this year. He meets the usual ultimate requirement for coaching greatness. But instead of giving him his due, many of us (myself included) sort of say "well, I'd have to see what he can do with a LESSER team before I can call him a great coach." And maybe there's something to that, but regardless, the dude can't win, despite having the unwavering support of Riley from the outset.
-J