Unicode is "designed to support the use of text in all of the world's writing systems that can be digitized"

Unicode needs tab, space, form feed, and carriage return.

Unicode needs U+200E LEFT-TO-RIGHT MARK and U+200F RIGHT-TO-LEFT MARK to switch between left-to-right and right-to-left languages.

Unicode needs U+115F HANGUL CHOSEONG FILLER and U+1160 HANGUL JUNGSEONG FILLER to typeset Korean.

Unicode needs U+200C ZERO WIDTH NON-JOINER to encode that two characters should not be connected by a ligature.

Unicode needs U+200B ZERO WIDTH SPACE to indicate a word break opportunity without actually inserting a visible space.

Unicode needs MONGOLIAN FREE VARIATION SELECTORs to encode the traditional Mongolian alphabet.