Incorporated into this mod: Simply Random
This mod is no longer being updated. See link above for replacement for versions 1.14.2+
This is a mod that adds a Cobblestone Generator... This is not a machine that makes power from cobble, but a machine that makes cobble, optionally using power.
Yes, you can use this in your pack... so long as the pack is not directly the source of any kind of income.
What Does it Look Like?
It looks like this
How Does it Work?
It produces cobble as fast as you can take it out. However, if you make it require power in the configs... then it turns into a box where power goes in and cobble goes out, speed limited only by your ability to harness it.
How Do I Craft it?
However, that can be changed by a modpack maker.
How Do I Make it Use Power?
To make it use power, find the mod's configuration file, and change the power requirement ("RF_PER_BLOCK") to be greater than 0.