The article mentions RLE, which is also incredibly good for integer IDs if you diff-encode them, since ids are typically sequential with no or small gaps. Diff + RLE can turn your encoded structure into ~1 byte.
Also, incredible website. The interactivity is so fun.
I did something similar to this very recently where I took a dataset and just continuously applied data encoding methods to it. It was much smaller in memory and compressed with zstd to a smaller size as well. I've found that 'prepping' data before using a generalized compression algorithm has significant gains both for encode/decode performance + the output size. These were, incidentally, CRDT operations :D
Your blog posts are great, keep it up
This needs an explanation.
But for other integer datasets there's FastPFOR
https://github.com/lemire/FastPFor
The linked papers there will talk about techniques that can be used to store multiple 32bit integers into a single byte, etc. Integer compression is pretty powerful if your data isn't random. The thing with UUIDs is that your data is pretty random - even a UUIDv7 contains a significant amount of random data.