Where can I find the whole trove

The emojinomicon and the entirety of its contents does not make itself known to any Hexbear. It is a process of submitting yourself to the Hexbear and, as a result, discovering the words of power to call forth thine chosen warrior.

and learn how to post them?

Just hover your mouse over them to see their :emojiname: - but use the emoji button in the formatting toolbar to open the picker which allows you to search for keywords like 'trek' or 'picard' (whereas typing : will only show you ones that match exactly what you enter)