Have you ever seen someone use amazingly-cool icons in-game? Well, if you want to start using these, feel free to take a look at the list that's supported by Minecraft. I tested these out myself.
Highlight the symbol you want to copy;
Press CTRL + c to copy;
Paste with CTRL + v in game. (Mac computers use cmd instead of CTRL)
Symbols:
Corporate:
Suits / Chess:
Shapes:
Blocks:
Music Notes:
Emoji:
Alphabet:
Astrology:
Flowers:
Hearts:
Arrows:
I probably missed a lot of the other options, feel free to add them to the comments below. I will update the list when possible.