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
King Suleiman ($161) King Suleiman was probably quite good when it was first printed, and djinn/efreets were more common to see, but these days its just pure nostalgia (and Reserved List, obviously!)
Ominous Steed Spectrier Beast/Effect/DARK/Level 6 ATK 2300/DEF 2000 Banish any monster destroyed by battle with this card
Cards like these and the aforementioned Open the GatesOpen the Gates are all green, so well lean toward that color when we get to our mana
Head came out good, very Goldbuggy
add 1 monster whose ATK equals its own DEF from your hand, Deck, or GY, then if you control a monster whose original ATK equals its own original DEF, you can Special Summon 1 monster whose ATK equals its own DEF from your hand