This deck with an ideal field can gain 350 life in one go just featuring the sorceries and enchantments not even the creatures....did that get your attention? Read on then.
Human, angel white mono deck. This deck pulls out tiny humans that buff each other enormously by how many other humans come out, swarm aggro style, and has ways of consistently ramping up the life, counters and creatures being gained for all, the angels then come and give over powered effects. All the high cost creatures are paid for with the use of Extraplanar Lens,and finally if the mana is ramped even by one lens, then the game ending eldrazi ,Ulamog, the Ceaseless Hunger can come out. The deck ramps so much mana so often it seemed almost silly to not add in at least game ender to the deck, Emrakul, the Aeons Torn would have been put in as well except that she costs even more, versus ulamog who can be played by turn 6. Also for functionality, no matter how this deck plays or starts out, it will always give everything first strike and some other bonus. For example, Archetype of Courage gives everything first strike and takes away the opponent's ability to have or gain first strike, this doesn't apply to double strike. True Conviction which gives first strike in the first hit and a second hit, while also giving life. Akroma's Memorial gives first strike,flying,trample,vigilance,haste, and protection from black and red, so no matter what, this field will always get first strike and something else.
Here's how this deck can pull off that life gain part that got your attention. First putting tiny humans out and then Cathars' Crusade, then playing Increasing Devotion puts 5 1/1 humans out there all becoming 5/5 humans by virtue of Cathars' Crusade which gives them all counters as they enter the field applying to themselves, afterwards playing True Conviction which makes them hit for 10 damage and gain life that way, then ramping mana to play the flash back cost of Increasing Devotion which will in this turn put, 5 (15/15) humans, and 10 (10/10) humans out not even to mention what creatures will be in play at this point. They all have double strike and lifelink which with the power of all those tokens, so when just those humans attack all at once, the life gain will be exactly 350 in that one turn. Other decks may have better ways of ramping life but this deck can put the hurt on.
Ideal starting hand: Champion of the Parish, Thalia's Lieutenant, Frontline Medic, Extraplanar Lens, and 3 Plains. Those can be played turn after turn until Champion of the Parish becomes a 4/4, Thalia's Lieutenant a 2/2, and Frontline Medic which gives all other creatures indestructibility when it attacks with at least two other creatures. The Extraplanar Lens allows most the deck to be played by then as well.
Side note for those who might be curious: The overpowered and stupid combos don't happen often, but during a recent playtest, by turn 7 I had Champion of the Parish as a 28/28, Thalia's Lieutenant as 26/26, Frontline Medic as 13/13 and 15 (10/10) human tokens. Cathars' Crusade, Increasing Devotion, and the counter gain from thalia's lieutenant and champion of the parish can become Very powerful very quickly. Enjoy!