Re: What chord can I finish off this progression with?
If you are looping, thene you need a chord that will pull you back to the first chord of your loop (Fmaj).
That will be:
C7 , Am 7 , Dm 7 (and then maybe changing the forst note to Fmaj 6) , Em , E aug (going chromaticly) or Gb dim (going chromaticly).
p.s. I know the E and the Gb aren't in key, but doing that will creat a tention that will be resolved in the F.
I hope I helped.