It's surprising to see Timur Gareyev on this list. He is the World Record holder for most simultaneous games played blindfolded (48). I watched the live stream of this record attempt and it was mind-blowing. He's well known as being a blindfold chess expert but he also does a lot of crazy stuff, like skydiving with a chess board: https://en.chessbase.com/post/timur-in-the-sky-for-chess-life

I can't find information anywhere on what his rules violation was, but this PDF says "Violations of US Chess Safe Play Guidelines." Those guidelines can be found here: https://new.uschess.org/sites/default/files/media/documents/us-chess-safe-play-guidelines.pdf

~~He was suspended for just 1 year, so I can't imagine it pertains to the more serious types of violation outlined in that document.~~

Edit: https://lichess.org/blog/ZNTniBEAACEAJZTn/breaking-the-silence