You can use these sutta checklists to keep track of the suttas that you have read. If you like to skip around, this will help to make sure that you eventually read them all.
These checklists are designed to be printed double sided, flipped on the short side, then folded into a booklet
You may also like to keep track of the whole nikayas you have read. For that you can use a Sutta Practice Life List.