If my hand contains a Faithless Looting, I would be okay keeping a hand if it was missing one of the pieces, especially if its a reanimation spell or mana as you have a larger number of those, but I wouldnt keep it if I was missing multiple pieces as youre not digging enough to consistently hit everything you need
The third, much less developed theme of this deck is having damaged characters under your control
She puts two counters on your stuff precombat, love that for free, and you can tap her with Simic color mana to double that counter on your dork or artifact
It might seem like this card has three different modes, but in most games you will be using either of the two more powerful ones: either kill a creature or kill a creature and make a 1/1 token
For the moment, lets set aside those discussions and instead just focus on these five new designs
Of course, what makes for the best MTG Modern Horizons 3 Commander deck will vary a little depending on your own personal playstyle and preferences, but hopefully, this will help put you on the right path to finding your favorite of the set