From an alias or mutual server

The /emote upload from_emote command supports any emoji you can get from NQN. It supports the following sources of emojis:

• Aliases
• Your packs
• Your mutual servers with the bot
• Recently used emojis in your server
• Any server aliases or packs you're subscribed to

You don't have to remember the exact name of the emote with this command, as it's got autocompletion enabled.