While there are fewer colorless commander options available than there are commanders of other color identities, there are still several powerful legendary creatures available for those looking to construct a colorless commander deck
Bonehoard Dracosaur is the common modern-day fusion of the two: the Mullslayer, if you will
You can also hit a player with a powerful creature and then double up on that damage by using this red giants fling effect
These are available in non-foil and traditional foil in Beyond Boosters and Collector Boosters
The White, Blue, and Black (or Esper) deck for Final Fantasy is built around Y'shtola, Night's Blessed, who incentivises you to cast multiple noncreature spells with mana value 3 or greater in a single turn to drain your opponents and draw cards along the way
The card roughly reads as whenever a player casts their Commander, draw a card, and its a whole lot cheaper to buy