I have about 30 1 gallon freezer bags full of greeting cards, 1 giant box with postcards, and then all kinds of odd bits in my desk. Plus a couple plastic bins with drawers for more stuff like stickers. I have way the hell too much stuff. These are in filing cabinets.
All of my pencils, markers, pens, etc. are in acrylic holders so I can see the color I want.
I have this stand to hold my alcohol inks, which I haven't even used yet.
I have found really great washi organizers on Amazon. Some spin around, others are clear plastic boxes. I haven't purchased one because I don't have the room and I don't buy washi much at all.
I have my postcards sorted by subject in the box and the same for the greeting cards in the ziplocs. Since I have so many and can't see them, I forget what is there.
I like to make greeting cards, but I have so many store bought ones, I want to use those up first. I have cardstock and papers in magazine folders. It's easy to see what I have. I have given away all of my rubber stamps, inks, and other card making stuff because it was going to go bad from lack of use.
I've tried doing large offers to get the cards out to people, but I have found that there's never that many people interested (like a 500 postcard offer). It ends up that about 150 or so will respond and then the offer goes stale. Seems like offers are only hot and responded to in the first 24 hours or less and then some stragglers will ask for some after the offer is flaired closed. I need to do small offers with pictures of the cards or focused on a certain subject.