Not sure if anyone still needs that, but I just found the last magicite I needed to get everything from the shop. And also figured out something that probably was intended at least to get it
The tree that you access from the spikes room, there is some suspicious area above in the map that looks like you could get to... but it's way too high. Seeing that there was a bat up there I thought of using the Feather Blade Ring since it resets jade feather (and also you get to jump again when you hit something). I totally skipped that it also says
A WALL. So you can simply diagonally hit a wall, jump, hit a wall, jump and you'll go up any wall. You'll reach a ledge and going up and right you'll find a very well hidden magicite. Found the rest exploring normally except this one. And now I could probably finish finding any other collectable if they are hidden like this.
Even after farming mobs for their clothes now I could get some weapons I hadn't got killing dozens if not hundreds of them. Probably useless by now that I finished everything else. No clothes from bosses though as I read someone got even with the dog set, the accessory and stripping them. I keep getting just blood after the first special drop.
Edit: just found another magicite shard in that same map all the way to the right in the middle, once you get out of the water and jump down. There is an item on the left in that screen, above and even charge high jump + high jump you can't make it to up there. The ring and jade feather trick lets you get it. That makes it... 11 shards? 3 weapons that need 2 each, that's 6. 4 pieces of clothing, that's 10. And this extra one, 11.