Minecraft – Way to make scoreboards appear with the /gamerule commandBlockOutput false command activated

My thought is to use a structure block, to clone the entity.

So this is what I'd do it:

• First, spawn an armor stand (as a marker) in the location of the entity to be cloned.
• Move the entity to a predefined location.
• Clone it with the structure blocks.
• Then move the entity back to the marker, and the new one where you want it.
• Finally remove the marker.

I'll just show how to set up the structure blocks. I'll assume you know what your doing with the teleportation of the entities.

So the cloning device should look like this:

(The command block in the second picture removes the stone block when a red stone block is placed there.)

So the structure block on the left is the saving block, you place the entities to be cloned on top of it.

You must have "Include Entities" set to on, or it won't clone entities.

The block on the right loads the entities. (If you use red stone to save, it will only save to RAM, not your disk, which is good.)

(The structure name doesn't have to be "cloner", but it just has to be the same in both blocks.)

When you have the cloning device set up, you just have to teleport an entity on top of the structure block on the left, place a red stone block in place of the stone one, then one red stone tick later, you'll have two identical entities.

Necro edit: I though I'd clarify why there has to be a red stone tick between them, its because structure blocks are "slow" (compared to command blocks) and require time to save the structure data. A single red stone tick is simply easy to do, but it can be any amount of time, as long as it gives the structure blocks time to do their thing.

Creepers have an ExplosionRadius tag to determine the size of the explosion. Because it's a Byte tag, it has a maximum of 127:

/summon Creeper ~ ~1 ~ {ExplosionRadius:127}

Ghasts have an ExplosionPower Integer tag, meaning the maximum value is 2,147,483,647 (which will most certainly crash your game when attempting to use it):

/summon Ghast ~ ~1 ~ {ExplosionPower:2147483647}

The Fireball entity also has an ExplosionPower Integer tag:

/summon Fireball ~ ~1 ~ {ExplosionPower:2147483647}

MinecartTNT, PrimedTnt, and EnderCrystal entities do not have any tags to determine the radius of their explosion.

You can find NBT data for entities here.

And general info on the NBT format (including minimum/maximum values) here.