uppercaseCHASE1, TheRealAlexBertie and FinnTheInfinncible, probably. Honourable mention to Stef Sanjati! I don't watch many trans girls on youtube but I like her content.
Chase's videos are really funny, he always looks like he's having a good time and he has a lot of useful resources- he's got that Trans 101 series and all his product reviews. His wall of prosthetics is really something! It's such a shame he's been hit so hard by the adpocalypse though :c You're So Brave is great too, they'll talk about anything under the sun. I loved the episode on music.
Alex is someone I feel like I can relate to, kinda. If I did go on T I'd have to deal with the same crap from the NHS (god, waiting lists!), so it's useful to have that perspective, and... Well, I just really like how he does his videos. Plus he has some cool tattoos! o: I thought about entering the art contest he had a while ago but I ended up not having time to.
Finn has a much smaller channel but still a great one. He doesn't just talk about trans things either, he'll say whatever he wants to say about what happens in his life and the people in it. He had some complications with his phallo surgery but I think he's just waiting for stage 3 now which is great! He seems like such a kind and loving person. Also, Lamby Cat <3