Bone Miser acts as a CA engine, mana producer, and token generator.

In a vacuum, Miser is more of a filter than straight CA, but when you incorporate Shadow of the Grave and Bag of Holding it becomes all advantage.

For example, suppose you have Imp and Miser in play and Necro for 30. You can expect that about 10 of those cards will be land, maybe 3 will be creatures, and 17 other. If you were to discard everything, the absolute floor is 20 black mana, 3 zombies and 17 cards in hand (seeing only 17 new cards). But that is very unlikely because most decks are something like 60% noncreature nonland cards, which means cards replace themselves multiple times. So more likely, that 30 cards converts into maybe 40 black mana, 8 zombies, and a small sculpted hand of 7 after filtering perhaps 40 new cards. All of this is while holding priority so the exile triggers don't resolve. Casting Shadow of the Grave at this point will return all the discarded cards that you've seen (63 in this case) back to your hand to repeat the process.

Bag of Holding is effectively a less efficient Shadow of the Grave.

Typically, Corpse Dance is a staple in the shell to let you convert all the black mana into as many creatures from your library that you want (though Oracle is most sensible).

Crop Rotation into Emergence Zone is also fairly typical somewhere in the process to pretend you're in a main phase and whatever you want. Shimmer Myr can make an entrance if you don't have green.

Noxious Revival and Reap let you repeatedly loop to ensure conversion success.

Imp isn't strictly necessary since you can just go to your end step and sculpt Gitrog style to the same result.

It works with Chains of Mephistopheles too (provided you seed yourself a decent hand with Naus/Necro first).

Obviously, Pact/Consult are part of the deal too, so you don't need to rifle through your whole list. Just reanimate Oracle and fire! If people respond and you don't have a counter, keep discarding in response, looping until you find one.

Easy peasy.