In 1.16.2 Pre-release 1, several fraction text symbols were given proper font support, resulting in almost all of Unicode's dedicated fraction and fraction-like symbols being supported by the game. However, there still remain some fraction characters which are not properly shown in the game:

⁄ Fraction slash
℀ Account Of
㏟ Square A over M
℁ Addressed to the Subject
㏆ Square C over KG
℅ Care Of
℆ Cada una
㎧ Square M over S
㎨ Square M over S Squared
㎮ Square Rad over S
㎯ Square Rad over S Squared
㏞ Square V over M

To reproduce, simply paste
⁄℀㏟℁㏆℅℆㎧㎨㎮㎯㏞
into chat and note how these render very differently to supported fraction characters:
%‰‱ ⅟ ½ ↉⅓⅔ ¼¾ ⅕⅖⅗⅘ ⅙⅚ ⅐ ⅛⅜⅝⅞ ⅑ ⅒