After a couple of moves, I started to consider getting more sleeves for CDs and LPs. I didn't care for this much previously, but it's annoying trying to pack all digipaks into moving boxes without getting them all scuffed up during the move. CDs in regular jewel cases = God-tier packaging that you can just throw into a pile and no problems!
Mostly I'm in a need for digipak sleeves. The digipaks F&V uses seem to be some standard size. They are not the biggest issue because the glossy surface is durable, but matte finished and more cardboard-like tend to get in worse shape quickly. How about bulkier and weirder sizes? Like Bomb the Daynursery 3xCD, Macronympha's Whorechestra or Mangled Clit's Erotakill.
Sarvilevyt used to sell some great LP sleeves years ago, not sure what brand they were, but they were clear and thin. I could also buy more of these if still sold somewhere.
I use these for my digipack sleeves, and they work great: https://www.amazon.com/dp/B09YVVKZ3F?plpRedirect=mhFallback&ref=clp_hp_h_pc&th=1
I have found that they can shift their size a bit, so they also work for some of the "deluxe" 2CD digipacks that I have as well.
I manufactured tens of thousands of sleeves in local plastic factory. In todaysa world, not really necessary.
German place protected.de is good to buy many kinds of sleeves for LP/CD/7"/10", dvds and so on. Also tip for labels who struggle to find mailers, or labels who want to silk screen to blank LP covers and so on. You can get a lot of stuff here easily.
Discoguard from holland has very nice ultra clear LP sleeves. I use some of these quite a lot. Unlike cloudy and grey'ish PP plastic sleeves, these look as clear and bright as cellophane sleeves. But a bit stronger than those sealed cellophane plastic protected is using. Also 7" sleeve here are better than protected sell. Or lets say, notch bigger so they fit more UG releases that are not standard paper single sleeve.
There are others too. Depending what I need, I choose specific supplier.
I have most of my digipak in PP plastic sleeves. Just like I got LP's in sleeves too.
ask your local labels, or even stores, if they have them made in quantity. For instance, Havoc Records used to have them made in massive quantities because they needed them for the label, but they also sold them in their mailorder shop. They were cheaper than anywhere else. Also might find a label with an unneeded stash.