This is a tough call because I like most of them...
Medvedev -- Clearly struggling the past 12 months, but also clearly a step above everyone else of his generation (on hard courts) when at his best. Also hilarious.
Berrettini -- I mean he seems like a nice guy.
Rublev -- His name is what made me a fan, and though his game and attitude has kind of turned me off him over the years, I still think his forehand is a beauty, and he also seems like a really nice guy, and he seems to have matured from what little of him we've seen this year.
Felix -- ANOTHER ONE WHO SEEMS TO BE A NICE GUY. Bit a wimp, definitely needs some eye of the tiger in him, but fun to watch play, someone who seems to be aware of the improvements he needs to make. Hope he can make them.
Sinner -- Never really liked him before, but since he battered Alcaraz at Wimbledon I have totally started to turn around on him. Hope he toughens up.
Rune -- So fun to watch when playing well. When things were not going well for him against Rublev we saw none of the tantrums he'd show on court last year when things went badly, so that's a big step in the right direction. What he did to Novak in Paris cannot be downplayed. He has massive upside.
Alcaraz -- Turns watching tennis into a fncking party. Makes the game fun again. He's had way too many injury niggles the last 6 months, and I hope they will not continue to derail him.
Alcaraz probably my favourite if I had to single one out, Musetti should definitely be on here too as I refuse to give up on him. Still hoping Coric will find some consistency too.
Honestly, I don't even mind Zverev, his inability to contain his ego is just kind of offputting.
Shout out to Tsitsipas and Shapovalov, who can be bags of fun to watch play, but whose general demeanor and attitude just kind of puts me way the hell off.