https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/bot.js#L118

I don't mind this blacklist existing, but I would rather they be parsed from a text file or something like that, and possibly also excluded from the git repo but that's up to you. If you embed this in the source code, you have to restart the bot every time you update it, or do something similarly nasty. If you update it in a txt file or json, all you need to do is run a command to update the list with the new contents of the file.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/fun/8ball.js#L10

suggestion
Strings should just be in a numbered array, and you use the random number as an index into it. No need for a long switch case.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/factions/clear.js#L37

If an error is caught, the parameter passed in the anon function is not the same as the then block. It will simply return an error that you're meant to print to the console for description of what went wrong. collection.size will always be null; you should instead be printing it directly, and assume that the entire command failed.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/factions/results.js#L12

This should definitely not be hard-coded. Please use the Date class to check if the queried year is greater than the current, then same for the month.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/fun/slots.js#L6

I really hate seeing emojis inside of source code. My intuition is telling me there's a more kosher way to do this.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/factions/1ups.js#L26

There should be no references to 'mario' or 'luigi' in the bot's code. Ideally, more than 2 factions should be supported, but for now I would work on refactoring this code so you're not repeating the same blocks of code twice when you could just be passing in parameters to a single function.

https://github.com/Phoenix1128/BattleBot/blob/0e8036a213d047f0370e6fa6fd571998215a233a/commands/factions/results.js#L29

This really needs to be data driven. An object which maps years to months, and months to faction battle data would work.