I really like QOI (The Quite OK Image format). It achieves similar compression to PNG, but it's ridiculously easy to implement (the entire spec fits on a single page), and its encoding and decoding times are many times faster than PNG.
I'm also a big fan of QOI as a simple imagine format.
Yes, it's not as good as PNG (as the sibling comments point out), but I view it more as an alternative to PPM (and maybe a BMP subset), as something that I can semi-quickly write an encoder/decoder if needed.
IMO, PNG is in a completely different level. Case in point, in the linked article the author mentions to not worry about the CRC implementation and "just use a lib"... If that's the case, why not just use a PNG lib?
https://qoiformat.org