Here are a lot of upright z-fold cards, but also some "regular" z- or s-folded cards. They sure are fun to make they can be varied in their layout :).
by Pretzl Cosplay
by Jenny W. Chan - Origami Tree
by Art & Craft by Anu
by sparklesjb1
by Sherufashion
by scrapdaworld
by little Crafting world