I could take several routes with the digipak. The one that first comes to mind is a CD: it's definitely the most common and accessible form of physical music that I've seen be distributed by independent artists within this scene, including some of my own musician friends. Bigger projects have also distributed on vinyl, and some have even done cassette tapes. I'm really interested in that last option. Cassette designs are always so cool to me, and I feel like I could do something really nice with the art.
Here's a photo my friend (shoutout Alice) sent me of her Sematary CDs. They all seem to follow a similar format inside, with some kind of related alternate artwork following the theme of the front cover on the inner slip and behind the disc, and the disc itself either being a black and white version of the front cover, the cover itself (for RB1), or a single cover (HAW). I've seen the backs and they all follow similar themes as well, with more artwork following the theme and a tracklist / production credits. I really like how cohesive and thematically distinct these designs are and if I were to go with a CD I would also try to emulate my branding through the design choices in this way. I was also thinking about making a little booklet to put in the inner front slip, since this is a common feature for lots of physical media.
Sematary has also put out cassettes for two releases, Rainbow Bridge 2 and 3. These cassettes are similar in branding to the CDs and include additional special logos and designs to fit the cassette structure.
Here I'll put some more examples of cassette inspiration:
Left to right: Machine Girl - ...BECAUSE I'M YOUNG...,
Puzzle - Laying in the Sand, SALEM - STAY DOWN (DJ MIX)