This thread would be a good starting place if you want to see what kind of videos people on the forum are watching about anime. Bear in mind that the membership on this forum tends to skew older than the average for anime fans, hence why a lot of the videos in that thread are about older shows.
The kinds of anime videos I look for on Youtube tend to be genre retrospectives and deep dives into obscure shows, older titles, and lost media. I imagine channels that discuss currently streaming shows are probably more popular, but if you're looking to start a channel of that type then bear in mind that's where there's the most competition against established channels.
The worst trend I've seen among anime Youtubers is the "anime is trash and so am I" mentality peddled by Gigguk and the like. You see it parroted by people all over Crunchyroll comment threads (or did until CR summarily axed comments recently). Sure, I enjoy the odd trashy show here and there, but I think it's damaging for anime production committees to perceive anime fans as self-deprecating idiots who are happy to wallow in any low-quality mulch that gets churned out. In an era when more anime is being produced than ever before, we shouldn't be afraid to have standards.
