When Steven Bartlett uploads his latest podcast episode on Youtube I instantly recognise it's his upload.
The guest on the right hand side of the image. Black background. White font, highlighted in red.
When Chris Williamson uploads a new video I instantly recognise it. Dark Blue background. Teal border. Guest on the right. Bold white font.
I think this is key component as to why Steven Bartlett's gained almost 3 million subscribers over the past year. His videos are now instantly recognisable.
Remove the logo from McDonald's Burger box and I could still tell you the brand. Remove the logo from a subway sub and I could still tell you the brand. Remove the logo from the a Nike billboard, I could still tell you the brand.
Dial in your fonts, colours, look of your thumbnails. This is your branding, so make sure your audience know it's you!