The main change was the chapter" riddles in the dark" - in the original printing Gollum willingly handed the ring over when Bilbo won the riddle contest. He did attempt other changes but these were rejected as they changed the tone of the book to much. He did make some later edits post Lord of the Rings due to the US copywrite expiring but these mostly changed minor lore details to bring it in line with the silmarillion.
I’ve got this on a sticker on my laptop so you definately can get it from red bubble