DJ mixes should be a go too, knowing that quite a bit of artists now heavily focus their new material on those outputs as well.
I also agree that pretty much anything for the most part that has material repeated from other releases or isnt even authorized by the actual artist themselves (comps, box sets, unofficial)
Live albums and singles are sorta stuck somewhere for me though seeing that they're always all over the place with the kind of material they provide. Artists like Burial would benefit from singles being included, but then you have some band like Muse where all of their singles listed on AOTY are all on albums anyway. You also have bands like Les Rallizes Denudes who only release live albums.