To be nitpicky, there's also 縦中横(tate-chu-yoko, "vertical mid horizontal")/横向文字(Héngxiàng wénzì "horizontal direction literal character") in which [0-9a-Z]{2,8} are placed horizontally in the middle of a line.

1: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/P...