I found a few different features that you can do with the text on signs in game, however I know there are a few other features that can be applied which I’m trying to find.
Here are a few of the text features i know:
<~#ffffff> - changes color with hex code
<~mark> - marks text yellow, <~mark=#ffffff> - marks it according to the color but a solid colour, <~mark=#ffffff/1> Marks it an almost solid color, you can see the text still but barely. (If anyone else knows how to change the opacity correctly please comment.)
<~rotate=1> Rotates the text in degrees
<~i> - italics
<~u> - underlines the text, color affected by <#ffffff> placed before it
<~s> Strikes a line through the text
There was also anther one I once saw that allowed you to change the text space but I do not remember how to do so. =P
Some of these do not work when you put them in your name and they are;
Edit: remove the ~ in the text, turns out these text features work here as well.