yeah to be honest I have no idea where most of these come from
I grabbed a few from aggregator pages like:
https://cyber.dabamos.de/88x31/index.html
https://www.88x31.nl/index.html
https://capstasher.neocities.org/88x31collection-page1
etc.

If you really care about proper attribution for every single 88x31, go find a better hobby/hyperfixation please.
HOWEVER if you made one of them and want credit (or for me to remove it) just let me know!