Key Doomsday Piles:

(keep in mind they do not always work every time and you must adjust the pile accordingly)

Meditate

Lotus Petal

Dark Ritual

Dark Ritual

Tendrils of Agony

For this one, you must play nine other spells before tendrils for this to work. Also, you need 1 Blue Mana, 2 Colorless Mana and one card draw spell post doomsday. Keep in mind you can change the dark rituals and lotus petal to anything you need. This pile is way harder to use, but it is more resilient to hate.

Brainstorm

Mental Note

Any Card (preferably Swan Song or Duress or Lotus Petal if you need more mana)

Laboratory Maniac

Unearth

First, draw a card and then play brainstorm to put mental note and the situational card you chose into your hand, and then put a random card and laboratory maniac back. Then play mental note, putting the random card and laboratory maniac into your graveyard. Afterwards, play unearth and any draw spell to win the game. Play duress and swan song as needed. You need 2U, 1B (or less if you chose Lotus Petal as your situational card), and two card draw spells to win after doomsday.

To upgrade, put in a Burning Wish package to tutor for anything you need. You can also add in some Pact of Negations for extra protection. There are also some piles you can make with Lion's Eye Diamond.

Thanks for viewing! :)