First, cast Isochron Scepter and imprint it with Final Fortune
Maybe flat out denial is more into whites ballpark for an effect like this
5 Madame Null, Power Broker Legendary Creature Madame Null, Power Broker is a three-mana 1/3 legendary creature with deathtouch, but more importantly, whenever a creature you control enters, you may pay life equal to its power to place that many +1/+1 tokens on it
The Triome cycle started in Ikoria: Lair of Behemoths has been completed, and these are great pickups for multicolor Commander decks, given fetchlands can find them to help with fixing
Because of that, Kess decks will nearly never run out of gas, consistently maintaining the ability to control the board
She importantly survives Let the Storm Rage On and Teeth and Ambitions, which probably makes her a bit better than Gaston