This has been a bit of an ongoing project over the last couple of years. Am totally aligned with @hip_young_gunslinger condition in terms of having a strange compulsion to hoard.
CDs/vinyl - Untouched and not going anywhere. The Bennos and crates stay. Although, I have circa 300 D&B 12"s that I bought as a joblot off a mate when he emigrated, with the intention selling them off on discogs for a steady but tidy profit. That’s still on the to do list.
Books/magazines - Have toned or significantly, but there’s a tension: MsWza is the set 'em free type, whereas I lean towards keeping. The “a pathway through our lives” thing defo resonates.
DVDs - I can be harsher with these cos I’ve never ‘collected’ then, just accumulated, and the repeat use scenario is a million miles away from that of a CD. For films I’m very meh, but I like having, say, BFI collections that will prolly never be available as freely as general release films. So they stay.
Clothes - have gone through a series of big big culls to the point where things are at an almost sensible level. Gawd knows how I ever accumulated over a hundred pairs of boxer shorts and the same for socks! It’s difficult, though. There’s a (pointless) attachment in some cases. E.g. I took photos of 40-odd t-shirts individually before chucking them. This is a HUGE thing for me in being able to chuck something out. If I have a photo, that’s 90% of the sentimentality dealt with. And it’s defo true that when you have a wardrobe you can navigate it feels like you’ve got more clothes than when it was packed out.
Paperwork - On top of this. Quite like filling and shredding.
‘General stuff’ - where the hell does it all come from? Knackered bike lights. Old phones. Dishes/keepsakes &c. Stationery. Car shit. Pointless toys. Christmas ephemera. Wrapping and boxes and packaging ‘just in case’. Tat. (We actually had an unopened box from three house moves ago labeled “Tat”!). Just fucking life detritus. Have almost shifted through and disposed of all of the unwanted bulk of this, now.
Anything saleable via eBay has been. Have easily notched up a couple of grand over the last couple of years or so just by steadily selling this and that. Failing that, gumtree. Next option is charity shop or free share/freegle/free gumtree. But, bugger me, there are some knobheads on gumtree. Took ages to give away a box of a hundred VHS tapes (which were photographed before being turfed out, naturally.)
Just HATE throwing stuff out into landfill, though. Properly hate the wastefulness of it.
Even stuff like broken bike lights that can’t be rehomed I’ve disassembled into recyclable bits, batteries for the box at the supermarket, and leftovers that can, finally, be put in the bin.
This whole tortured process finally got us to the point where we could see the wood for the trees and have a damn good spring clean of surfaces etc, and get things in some sort of order.
Then, just as we’d turned the second bedroom into an actual useable bedroom rather than a heading dumping ground… Hello baby stuff! 
It’s all very draining.