King's Forge

" means "full" height (only room left for the board and manuals on top)
"0.5" are half of that height and can stack.
"0.25" are quarter height; while they will stack, they are a little loose, so I don't actually recommend using these. However, I can see them being useful to hold the playing set of Gather cards, or something like that.
"x1" means a single stack of cards can be held
"x2" means two stracks, joined on the long side
"x2v" means two stacks, joined on the short side
"x4" means four card stacks joined togethe