I think this one should be needed, being able to set the requirements for blockheads to spawn in.
You would be able to set what items are required and the amount of time crystals.
So for example you needed a jetpack and a diamond and 200 time crystals to spawn in a blockhead that would make a challenge.
Please do note that maximum tc settings will be 200 and minimum will be 20.
Every item would be available but depending on their expenses you will be limited to how many you can choose to make things fair.