The second had 40x40 buttons, then the third had 88x31...
Ironically the best place to find this evidence is in books. Head on over to archive.org, find some mass market "how to use the web" books and they're full of screenshots.
You could also do wayback machine but during the "folk art" era of the web, there was long forgotten web properties run by "just some person" with names like "web fairy's daily roundup" with these long links like homesite.unc.edu/~rhonda/links.htm or whatever.
The fetishism for dot coms is probably post-1997
When you go through these old texts it's a sea of sites you have never heard of. Some of those are in the wayback, a lot of them aren't.
You can clearly see the eras. There's also some promotional videos such as
https://youtu.be/-1l6aBgX5UY?si=UioQTDenqHelQc07
88x31 is where most of the effort has been placed on the archives and so I kind of just pass over that one
The last thing is the hypercard cross-over ... there were many users and creators that went from that platform to the web and they took their hypercard design language with them.
The 88x31 might be called the first post-hypercard era.
GIF wasn't a widely used raster format of the 1980s. That would be PCX, MSP (pre BMP), PIC (Macintosh PICT), IMG (GEM), TIFF, Dr. Halo (CUT/PAL), TARGA...
None of the 1980s image formats are in use anymore except for Postscript which is a programming language so it doesn't really count. The TIFF of the 1980s (the kind that NextStep generates for instance) won't even open in modern imagemagick with libtiff stripping that support 15 years ago (along with a lot of other companies ebullient artistic license of the TIFF standard). Modern TIFF uses standards dated post 2000.
If you need to open a TIF dated from the 1980s, hit me up, I've had to resurrect these parsers before.
Regardless, this is really interesting!