Currently, my most watched would be Kanna Yanagi. (probably a bit obvious with how many of my posts include her)
I think why I watch her so much is because she's reliable. She's streams a lot, so there's always more to watch. She maintains a comfy and wholesome vibe, so I don't have to worry about "stuff" like world news or internet drama while I watch. The big collab events she joins or organizes are also a bonus.

That would probably be Fauna/Nimi.

As for why, because she’s the queen of yapping.

I’ll usually tune in to whoever if they are playing certain games I wanna see someone I like play, but with Nimi I’ll watch just to hear her talk endlessly.

I primarily watch clips, so for the most part it’s whoever YouTube decides to recommend. Which at least over the last year or so has meant I’ll get a lot of the same handful of people recommended for a month or two then it’ll cycle to another set of people. Typically it’s been 5 or 6 different hololive members, one or two PhaseConnect members, and one or two VShojo or VShojo adjacent members with the occasional indie mixed in.

Lately it’s been a lot of Korone, Ollie, Ceci, Gigi, Sora, and Subaru from Hololive, Pippa and Lia from PhaseConnect, Ari, Haruka, and Zen from VShojo, and Yuzu, Sinder, and Vedal/Neuro from the indies.

When I do pop into a stream, it’s typically collab streams or any stream where Ollie is being especially unhinged or Sakura Miko is trying to speak English.

Jeremiah Phillips. Hilarious stuff that always makes me laugh when I am in a shitty mood.

Lately I’ve been watching Pippa Pipkin because it’s morning here when she streams so I tune in before I go to class (I like to waste my mornings with YouTube). I don’t know anyone else who consistently streams on YouTube around that time. She always comes up in the recommended page.

I watched quite a lot of Kronii and Reine too before.

I try to watch KitaroVT when he’s on. The vibes are great, the emote set is great, he makes a costume for every game, and his regulars/friends are hilarious and awesome wingmen.

The first VTuber I everr actually watched was Shirogane Noel. But my most watcher VTuber is probably Ouro Kronii or Dokibird.

CoreOfMidas

A very honest, authentic kind of weird. Tends to come up with golden rants from time to time. Also, very artsy and has made some songs.

Technically Henya, in that I’ve seen multiple videos by Henya. She played Black Mesa and I’m a sucker for Japanese dorks getting into important shooters. (The Halo CE co-op with Zentreya devolved into too much teamkilling. I mean, that’s also how it worked back in the day, but it’s more fun to do than to watch.)

Wait, does Shenpai count? The combination of manic energy and neverending bi panic make for good edits. The only full stream I’ve watched was Mario Party because it had JoCat, RTGame, and Ray Narvaez Jr.

Kirsche Verstahl. She reminds me of a more serious Mister Metokur.