Kess Advanced cEDH Competitive
The next level of Kess is here! Will be updating with more description soon.

Main Win
Demonic Consultation + Thassa's Oracle or Tainted Pact

Demonic Consultation + Jace, Wielder of Mysteries or Tainted Pact

Backup Wins
isochron scepter + dramatic reversal + copy artifact + lightning bolt - shoot everyone to death

isochron scepter + dramatic reversal + copy artifact + swan song - make infinite swans

Aetherflux Reservoir + Dramatic Reversal + Isochron Scepter - plus 2 mana from non-land sources. Shoot everyone to death

Aetherflux Reservoir + Bolas's Citadel + Sensei's Divining Top - draw your whole library, gain a ton of life and shoot your opponents to death

Aetherflux Reservoir + 17 spells - gain 153 life to activate reservoir 3 times and kill opponents

Other Noteworthy Combos
Bonus Round + Demonic Tutor - this is a combo that we can use to grab two different tutor targets. We can also do some shenanigans with this. If you have threshold ( 7 or more cards in GY ) , you can grab cabal ritual and dark petition as your two tutor targets. The ritual makes 5 black mana which we use to cast dark petition. Since bonus round is active, both spells get copied. We end up with 11 black mana and two tutors, 5 from the second cabal and 6 from both dark petitions. We can then chain into any number of crazy things to do. The easiest thing to assemble here is Bolas's Citadel + Sensei's Divining Top which we can use to whittle through our library until we find the cards we need to win. You could also just grab and two winning cards here for instance jace and demonic consultation. There are many other combos that can work out here I will list in the future.

Notion Thief + any wheel - angry opponents and you draw a lot

Narset, Parter of Veils + wheel - another notion thief type combo, slightly worse as they still will draw 1 card

Waste Not + Wheel of Fortune or Waste Not + Windfall - super card advantage and mana

Ad Nauseam - try to play on opponents end of turn to untap w the cards you need

Dramatic Reversal + Isochron Scepter - with a few mana rocks, infinite colorless mana and untaps if needed

Bonus Round - copy lots of spells fast. play it from the GY using kess's ability for 3x spells