YAML - YAML 1.2 --- YAML: YAML Ain't Markup Language
Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
TOML - TOML - Tom's Obvious, Minimal Language
Characters - Characters makes it easy for writers, designers and developers to access special characters. They are easily found and copied to your clipboard, either as html code or as the character itself.
JSON - (JavaScript Object Notation) is a lightweight data-interchange format
Qwik - The HTML-first framework. Initialize apps of any size with < 1kb JS