W/B Grindy Midrange Control @ Pauper - Pestilence & Lifegain (Pauper)

This a midrange-control type of deck, that wants to go into the long game to find the combo of Pestilence and Guardian of the Guildpact to secure the win.
Occasionally, the flyers + the lifegain + the threat removal are enough to win, but I'd say 4 of 5 games come down to finding and using Pestilence.

Since it can stop creature aggression on so many levels (block on the ground and in the air, gain life back, remove, prevent damage) and has a decent amount of card advantage, the deck can usually get to the late game against creature-based decks of any kind. Fairies and Delver decks are really good matchups for this deck.

Against control, it's important to build up the mana necessary to be able to cast several spells per turn, in order to force the opponent to decide which spell they want to counter. The deck usually has enough card draw and life gain to get to this point.

Combo decks are the hardest matchups, since this deck wins slowly. In these cases, it can only hope that part of the combo is a creature it can remove. If the combo pieces are artifacts or enchatments or lands, the sideboard offers a lot to shore up this weakness. Prismatic Strands can also negate combo decks for the few turns the deck may need to win on it's own. The Tron + Dinrova Horror blink combo was a nightmare for this deck when it was on top of the metagame.

The burn matchup can be difficult if the deck does not find the early lifegain, and easier when it does, specially when it also finds Prismatic Strands.

Guardian of the Guildpact is the secret star of the deck. For most decks, it is impossible to kill (Agony Warp kills it, but that's not widely played, and as long as the deck has a secondary creature out, sacrifice removal does not work), and either slows aggressive creatures (Gurmag Angler!) down or, in multiples, kills inside of a few turns.

Mainboard graveyard hate is really effective against so many Pauper decks. Kor Skyfisher can bounce Bojuka Bog as well, and since this deck goes into the late game, it is rather common to exile the opponent's graveyard twice in a game.

All in all: if you like grindy, creature-based, highly interactive games, then this is something you might want to give a try :-)