Replace Hymn to Tourach with Wrench Mind and Cemetary Gate with Gray Merchant of Asphodel and you got a mono black version of this deck for MTGO. This deck is pretty much a more defensive approach to the classic Mono Black Control decks,which can work but especially if going with Gray Merchant of the Asphodel than you'd want defensive black creatures rather than colorless walls.
Before talking about casual combos, I think many people here forgot that there is 1 top tier combo deck that has been around for like forever and isn't going anywhere anytime soon, yes guys: Affinity! Atog+Disciple of the Vault+Fling(or even just Atog+Disciple or Atog+Fling but those will require more artifacts on the board) is the combo in case you guys forgot. Well, technically I guess aggro/combo is the more accurate description for the deck seeing that more often than not you can win with Carapace Forgers and Myr Enforcers just beating down the opponent to 0 rather than get the combo online, but the combo is still there and also gets plenty of wins for Affinity. Also, as a deck Affinity has all the characteristics that other combo decks have: card draw to get the combo pieces online(though no tutoring) as well as means to protect the combo(other strong creatures to bait removal and for edicts as well as Atog's built in pumping ability and casting Fling in response to removal).
In the same manner, there is also the Goblin combo variant with Kruin Strikers along the usual Foundry Street Denizens and those red sorceries that produce 1/1 goblin tokens in droves to pump the Strikers/Denizens with Death Spark, Lightning Bolts and the other goblins clearing the rest of the board and using Sylvanok Lifestaves to stay alive long enough to win. Again, more of an aggro/combo deck than a classic combo variant, but still has the combo element on a top tier deck.
The reason I mentioned these decks, that I'm sure everyone here knows(especially Affinity) is because these decks are tried and proven and at least Affinity has been winning consistently for many years. The pure combo shell doesn't work in Pauper nearly as well as in other formats due to the shaky mana base Pauper has, the over reliance on creatures in the format and extremely limited tutoring abilities. Thus, being a format that is so reliant on creatures already, the aggro/combo shell fits perfectly. Control/combo also works obviously, as the various Temporal Fissure decks have shown, but without Temporal Fissures the other options aren't nearly as powerful nor consistent, but it can certainly still work. Pure combo on the other hand like some of the variants mentioned in this thread are either too slow, too inconsistent or simply unable to protect their combo from removal/counter magic to really shine like in other formats. Thus I think that in Pauper combo decks should be built on either an aggro or a control shell, resulting in aggro/combo and control/combo decks rather than pure combo, if you want to play combo competitively that is.
In the same manner, there is also the Goblin combo variant with Kruin Strikers along the usual Foundry Street Denizens and those red sorceries that produce 1/1 goblin tokens in droves to pump the Strikers/Denizens with Death Spark, Lightning Bolts and the other goblins clearing the rest of the board and using Sylvanok Lifestaves to stay alive long enough to win. Again, more of an aggro/combo deck than a classic combo variant, but still has the combo element on a top tier deck.
The reason I mentioned these decks, that I'm sure everyone here knows(especially Affinity) is because these decks are tried and proven and at least Affinity has been winning consistently for many years. The pure combo shell doesn't work in Pauper nearly as well as in other formats due to the shaky mana base Pauper has, the over reliance on creatures in the format and extremely limited tutoring abilities. Thus, being a format that is so reliant on creatures already, the aggro/combo shell fits perfectly. Control/combo also works obviously, as the various Temporal Fissure decks have shown, but without Temporal Fissures the other options aren't nearly as powerful nor consistent, but it can certainly still work. Pure combo on the other hand like some of the variants mentioned in this thread are either too slow, too inconsistent or simply unable to protect their combo from removal/counter magic to really shine like in other formats. Thus I think that in Pauper combo decks should be built on either an aggro or a control shell, resulting in aggro/combo and control/combo decks rather than pure combo, if you want to play combo competitively that is.