I honestly don't know, other than the ones I already mentioned. The Luigi one needs a slight update anyway, and if you want, I could try to rip a definitive Mario sheet, thereby eliminating the need for all of the ones currently there.
That would be a great idea. And what is Luigi missing?
Well, looking at the "master" sheet and the Hammer Bros sheet I can see that there are some rear sprites that are on the HB sheet, but not on the master. I'm sure it's the same case with all the others.
'K, I guess I'll get started on some of this soon.
To answer your question, A.J., there's some unused SMAS-Battle sprites of both bros. that deserve recognition. Also, I'm probably going to post a minor update to this sheet (doomship anchor, derp) and to the e-Reader sheet (I was informed that the block I added had four frames of animation, and a couple other things' palettes are completely wrong).