I appreciate the different Mania logos, whether its font based or hand drawn. Actually the whole handmade approach to his releases is something to admire.
The mirrored collages found in the later ZSS works are also well done. "Spectacle of the Triumph", for example, had some well put together designs.
As for covers -- I've always liked the painting for the first Vihanmiehet album and I think it matches the theme well. End of the world / rubber fetish vibe. Would be cool to see that as a shirt graphic.
It also helps when the visual art is related to the sounds themselves. Clinic of Torture, for instance. Pretty sure most of, if not all of those photos were taken by the artist and aided in the recording process. There's a sense of realness there. Or someone like Gnawed using images of the sewers he explored for his recordings.