Some initial resources/links.
There have been articles on vloggers for a few years now, as mainstream media slowly catches on to what teens are doing (which often means not accessing mainstream media!). Look at both up to date and older articles to get a sense of how quickly or slowly such fame and popularity comes and goes ... do tween/teen vloggers keep their audience as they go beyond their t(w)eens?
I see Zoella's bro, Joe Sugg, is on a 2014 Huffington Post top 25.
Useful for the 2019 vlogger brief: Amber (YT).
MTV's 2017 list features some younger examples.
A Mom's site may lean to the more conservative (but drops in some familiar names)
Top 19 YouTubers globally according to BusinessInsider data. MediaKix has a different list.
A list of UK vloggers.
Teen Vogue list.
Top vloggers tips.