Rakdos Burn using SOI madness cards to do large amounts of spell damage.
The Burn: Fiery Temper and
Alms of the Vein
deal 3 damage for 1 mana as long as there is a way to discard them.
Exquisite Firecraft
will help close out the game and should be uncounterable by the end. This totals 40 burn damage to throw at your opponents face. Molten Vortex also turns any land into a Shock which will help close out games and eliminate dead draws.
The Madness: Fiery Temper and
Alms of the Vein
need a way to discard them so we use
Heir of Falkenrath
and Tormenting Voice to discard them while adding damage and card advantage respectively. Avaricious Dragon can also help but it is mostly used to grant card advantage late game.
More Card advantage! The deck needs to dig deep for its burn or creatures threats. For that we use creatures who generate card advantage such as Sin Prodder, and Avaricious Dragon. Also, they are both an evasive threat on their own.
Creature Burn: These two creatures help deal direct damage to the opponent. Goblin Dark-Dwellers will always have a burn spell to recast from the graveyard making him do 3 to 4 damage instantly and then becoming an evasive threat on the board. Chandra, Fire of Kaladesh
adds damage to every every red spell with her untap ability. As well when she flips and does 2 damage every turn until she can ultimate. Or take out small creatures if she needs to protect herself. She is easy to flip with Tormenting Voice and Fiery Temper or Goblin Dark Dweller and any red spell will turn her over.
Side Board:Asylum Visitor helps with drawing more cards for a control game, also works well with Avaricious Dragon
Act of Treason helps turn around games that the deck has lost board advantage. If they drop a big threat it turns back on them.
Radiant Flames
Is good against small creature decks
Virulent Plague is good for token strategies.
Transgress the Mind
and Infinite Obliteration work for big threats or spells that might disrupt the deck.