#characters #ASCII
Whitespace
9 character tabulation
10 line feed*
11 line tabulation
12 form feed
13 carriage return*
32 space

*line endings

MS Windows files use CR+LF as line ending.

#characters
Arrows
⇐ ⇒ ⇔ ← →

#characters
Cool brackets
❨ ❩ ❪ ❫ ❬ ❭ ❮ ❯ ❰ ❱ ❲ ❳ ❴ ❵

#characters
Generalization, derivation
《 》