Are there any rock albums entirely in minor keys?

Cafe Society
1

Or at least in excess of 80% of the tracks?

2

Hate Songs in E Minor, Fudge Tunnel.

There are probably hardcore and metal bands who have never played a song in a major key.

3

Yeah, I was gonna suggest that you’d have a hard time finding any heavy metal that wasn’t in a minor key.

IIRC from the sheet music I’ve seen, Prince tends to write in B-flat minor, but I haven’t seen what I would consider to be a representative sampling.