Wafflem found and updated some more old levels from a lot of different people: Andi, Ben Conway, Fleech, Gaston Splatt, geoo, GM, Gui55, Insane Steve, insulfrog, Isu, Jazzem, JM, Leviathin, MCMarshy, Mindless, Mikau Schekzen, Minim, Mr. K, Pieuw, Proxima, ssam1221, timballisto and several community levels.
I added these levels to the existing packs and updated the download links in the first post of this thread.