Most of mine end up in the PPJ. Plastic pokemon jail. For everything else, they go in folders. Or random tins haha
Soft sleeve with the opening facing down, then into a 9 pocket binder page, then in premium binders with D-shaped rings. The binders themselves also have rigid slip covers for protection.
However I have sets, not bulk.
I’ve been using these for twenty years:
www.ikea.com/us/en/p/glis-box-with-lid-clear-00283103/
They can fit 6 stacks of sleeved cards, and in the side area I put sleeves, accessories etc.
I store most of my expensive or favorite cards double sleeved in a dex protection binder. Extra cards that I wouldn’t quite count as bulk but don’t care to put in a binder like normal V’s I sleeve and put in a deck box.
Ring binder, stored horizontally.