I wrote this blues song with this chord progression:
High Cminor-Fmajor-HighCminor-Gmajor-Fmajor...back to High Cminor.
What chords would harmonize well on slow blues progression?
The IV-I cadence at the end is a little unusual for Blues, but it's not un-heard-of. Songs like The Butcher by Leonard Cohen use the IV-I cadence because of its religious connotation (it's the "Amen" or Plagal cadence, historically older than using the Dominant).
In a similar sort of vein, you could trying building Bluesy song on some of the other modes, like Dorian and Lydian. Dorian has a major 6th in it which is a little eerie in the overall "Minor" kind of sound. Lydian has a sharp 4th in it which is a little eerie in the overall "Major" kind of sound.
So basically your chord progression is this :
Cm F Cm G F C
The most common blues progression is consisted of 12 bars, as such:
Cm Cm Cm Cm
Fm Fm Cm Cm
G G Cm G
and variations on that.
I'm not sure about how many bars you have of each chord, but you could work your way around the blues progression with your chords like this:
Cm Cm Cm Cm
F1 F Cm Cm
G F2 Cm Cm
1 This is a borrowed chord from the C major scale. Instead of using F minor, we borrow F major. Usually it's the other way around, but if you want to use F major, this might be of use. Also you can transform the second line of the progression as such:
Fm F Cm Cm
2 It's not uncommon for the V to move down to IV in blues/rock n roll.