I like the effect on the images used on this Spotify page, and out of curiosity I'm trying to replicate it in Illustrator. It's not a simple multiply mask, and seems a more involved than the kind of duotone I can do in inDesign.
On paper, they'd be high-contrast duotones. Or, possibly monotones printed on colored paper with opaque inks (such as via screen printing).
Possible other ways to describe the effect would include:
This is called a duotone effect, the first one is a duotone effect that just has some texture added to it.
You can expand on this by trying out more colors, performing this on a texture and then overlaying on a photo or anything else.