I just found out that Tove Jansson did illustrations for The Hobbit back in 1960. Some more info and pictures:

https://tovejansson.com/hobbit-tolkien/

https://shop.moomin.com/products/the-hobbit-illustrated-by-tove-jansson

Interesting that she drew Gollum as so large. The page above notes that Tolkien added a note about Gollum's size in later editions of the book because she wasn't the only one that did that.