What is the legend?
I am sure during your time on dA you have seen people using emotes within comments, forum posts, journals and various other places around the site. Out of the thousands of emotes on dA, there is only around 300 that can be used anywhere, and these are all listed in the Emoticon Legend.
You can access the list of emotes available by clicking this link. On the right is a copy of all the emotes available, and down the left are the codes needed to make each emoticon appear.
For example typing :hug: will produce
Some emotes have more than one code, eg can be produced by typing either :) or =) while others appear on the list only once.
Please also note that the codes are case sensitive. Therefore typing :HUG: or :Hug: won't produce the emote.
How do I get an emote onto the Legend?
The simple answer is ... you don't. The legend does get updated from time to time, however this is only on special occasions. Which emotes appear on the Legend is down to dA core staff and it is unlikely any new emotes will be added in the near future.
All official changes to the legend will usually be announced by mattdanna but there is no point asking him about these things because the more you ask the less likely is it he'll do what you asked for.
What are the weird emotes on the legend?
If you take a look down the list you may spot some unusual emoticons which often have codes that seem random or unconnected to the actual emoticon. These are commonly emoticons to represent past and present dA staff + volunteers. If you select the Sort by Category option and look under the "DA People" header you can see a full list of such emotes.
How do I find the creator of a legend emote?
Within the Legend there is an option to Sort by Creator. By selecting this option it lists all the original creators next to the emotes.
To quickly find an emote's creator you can often use the quick search function in your browser (commonly ctrl + F) and type in the emote's code.
Can I freely use emotes from the Legend on my forum/webpage?
Generally, no. As stated at the bottom of the Legend, "Emoticons found at or in use by deviantART are not freely available for use by other websites. If you would like to use these emoticons or any of the others found at deviantART, you must contact the creator of each emoticon desired to obtain permission for use."
Therefore always seek out the creators permission if you wish to use it.