There are a huge collection of unicode faces, symbols, and other icons you can use in chat, signs, and anvils called smileys. You can view the full collection by category using the /smileys command.
Emotion smiley keys
In addition to writing smileys individually, there are also emotion keys which produce a random suitable smiley, so you can quickly insert a face of the select emotion. The keys are written as any other smiley