It should be Horford then Irving, and that's probably it. Brown and Tatum look great, but I don't think they're on track for an All-Star game just yet.
Horford is off the charts right now. He's shooting 64% from 2PT, 44% from 3PT and 84% FT. He's top-20 in rebounds & top-40 in assists. Offensive rating of 120 and defensive of 97. All of that with 15/9/4 which not many can match in counting stats.
Irving has been very good, too, but if he's still seen as offense-only he could potentially draw a snub with his current averages.