Aside from maybe .bmp, that never really existed (though .bmp has palletized colours, I guess?).

Just like you can assume most PNGs to be lossless (despite supporting pallettes, which pngquant uses to "compress" them) and non-animated (despite APNG being over 22 years old), you can assume most AVIF and WebP images are lossy. Same with JXL. HEIF requires a bit of special care (it's only produced by devices with HDR support so your pipeline needs to fit that) but that's pretty much it.

You may get surprised by an accidental, huge lossless AVIF/WebP/HEIF file, but most sources where you can even get these files are all lossy. Unless you recompress your photo library yourself, of course, but then you have full control over the entire process and can decide whether or not you want lossy or lossless.