Thumbnail makers? If you're talking about sites that automatically generate thumbnails, you're probably not gonna get anywhere with those. If you want some free tools to make thumbnails, what I personally use is MS Paint, LunaPic, and Google Docs. LunaPic is online, no sign up, free, and provides a lot of tools to edit pictures. You can blur, adjust colors, brightness, add borders.. Very good tool. Google Docs, I mainly use that for layering. I can put the background image and then any other transparent images on top of it, so it's kinda like dragging and dropping. And then I screenshot that and put into MS Paint for finishing touches (like resizing to 1280 x 720 or cropping, etc.)
If you want some good fonts, Cool Text Graphics Generator is good for words. You can generate words for your thumbnail in custom fonts and then you can copy and paste that into Google Docs to move at will.
It's easy to get the hang up, and all free. I know there's other tools like Paint.net or whatever, but that's just my style.
