I have not done a deep search on Gooogle to find a list of all the codes with special characters in HTML, but I have found a few, not with much records.
The character I was looking for was an arrow pointing up.
What I did was (with Eralper's help :)) select the character from Microsoft Word, save the word document as html and view its source. Here it is: ↑
You might still need those kind of lists to check the HTML standard.