Superscript
Replaces character with superscript version.
Historical Forms
Replaces letters with historical variants that may appear anachronistic today. The best-known example is the long form of s.
Small Capitals From Capitals
Turns caps (and sometimes also numerals and punctuation) into small caps. Mostly used together with Small Capitals feature to get an all-small caps setting.
Ordinals
Replaces characters with ordinal forms for use after figures.