Which power cords help ameliorate digital glare/grain/digititus?

Ya gotta be real careful of that arthritis, dude. It’ll make it all the way up to the brain.

Everything makes a difference.   I would be sure your digital equipment isn't contributing before looking for cables, etc.  Why look for zebras when a horse is over there.

I have found that power cords can help with noise and EMI I found the biggest improvement in my digital library was my DAC. I have a Krell Digital Vanguard and initially I thought cool an internal DAC great until I got an external RME-ADI-2 DAC running balanced interconnects into my Krell. All I can say is WOW. I love my vinyl but the change in depth, warmth and clarity is amazing! 
This is worth every penny of under $1k