Combo:

With the new Warlock Quest, you are able to play a 0 Mana Glinda Crowskin, 6 Mogu Cultist's, [Hearthstone Card (Grim Ralley) Not Found] the [Hearthstone Card (Glinda Crowsking) Not Found] and play the seventh Cultist for 8 Mana total to Summon Ra. This is also possible, if one Glinda sticks on the board. You can always shuffle in new copies with the Glinda Crowskin and Baleful Banker combo.

Against Control Warrior and the likes you might need to play several Ra's, which can be achieved by adding a copy to your deck with Baleful Banker. With 0 Mana Banker's, you can shuffle in more copies, if the opponents armour total is too high for 2 Ra's. Most of the time, against control Decks, you have the time to delay your combo to set up for several Ra's.

Card Choices:

1x Plot Twist is good for completing the quest faster and also comes in handy, if you draw your combo pieces early, even though you don't need them yet.

The Handlock package (Mountain Giant, Twilight Drake, Sunfury Protector) is good to absorb opponents resources, that otherwise would do face damage, plus you can create some huge taunt minions. I am not sure though, if they are the best choice, feel free to suggest replacements to further improve the deck.

1x King Phaoris is good out of the same reason as the Handlock package. Plus, in Hunter matchups, by turn 10 they often lost their steam, but already did enough damage, that you won't survive much longer due to chip damage, such as the hero power. Dropping King Phaoris with a Twisting Nether and a couple of other spells on hand is often the only way to win the game.

1x Mossy Horror is decent on its own in this meta (at least at rank 15 XD) and in combination with Curse of Weakness it functions as a board clear, while keeping up the tempo.

The hardest matchup is Quest Shaman, because they have a pretty decent start and with their new hero power, damage battlecries going face take you down quite quickly.

As I already mentioned before, if you have any replacement suggestions, comment them. I will try to keep updating the decklist.