A superficial search leads to things like https://www.rapid7.com/db/modules/auxiliary/dos/http/gzip_bo...
https://stackoverflow.com/questions/1459673
You really want to be careful about potentially breaking laws ...
If FB supports brotli, a much bigger compression factor than 1000 is possible, apparently.
There's also a script in that directory that allows you to create files of whatever size you want (hovering around that same compression ratio). You can even use it to embed secret messages in the brotli (compressed or uncompressed). There's also a python script there that will serve it with the right header. Note that for Firefox it needs to be hosted on https, because Firefox only supports brotli over https.
Back when I created it, it would crash the entire browser of ESR Firefox, crash the tab of Chrome, and would lead to a perpetually loading page in regular Firefox.
It's currently hosted at [CAREFUL] https://stuffed.web.ctfcompetition.com [CAREFUL]
[1] https://github.com/google/google-ctf/tree/master/2019/finals...
This means you can serve 1M payload and have it come out to 1G at decompression time. Not a bad compression ratio, but it doesn't seem like enough to break Facebook servers without taking on considerable load of your own.