Here is a list of ideas that bot users would be able to use to unlock new gameplay options. Apologies if any of them already exist. Hopefully some of them might get added.
  1. Subscribe to player status effects being added or removed.
  2. Being able to set the duration of status effects that are set via commands.
  3. Being able to set the max cap for HP for a server.
  4. Being able to change or disable natural HP regen.
  5. Subscribe to player damage taken. Includes source and amount.
  6. Subscribe to heart flowers being obtained. Alternatively, subscribe to max HP being changed.
  7. Subscribing to player HP going above or below a certain amount.
  8. Subscribing to players being revived or respawning.
  9. Being able to set the attack multiplier for all mobs.
  10. Being able to set an HP modifier for all mobs.
  11. Subscribe to mob becoming aggro, including the name of the player who aggro'd them.
  12. Get the stats and location of all players in game in a single command.
  13. A hardcore mode, where players who are killed and not revived are auto-kicked from the server. The options would be to turn it on, off, or reset (allow kicked players back). This one isn't so much for bots, but would allow people to make hardcore servers without needing a bot.
  14. Wacky clear chunk. Deletes all loose (not held, in storage or on hooks) items in a chunk. For dealing with griefing.
  15. Subscribe to high fives.
  16. Be able to get the number of friends a player has via command.