Of all the decks I ever made, the one I played and tweaked the longest was a green-blue deck that I played at the very first Magic World Championships
Cards that allow you to play extra lands, such as Exploration, Burgeoning, and Azusa, Lost but Seeking, provide tremendous amounts of ramp
Combine it with cards like Arcane Adaptation (which changes the type of every creature you control to another of your choosing), and you can easily start locking players out of the game
Granted, most are raw artifacts which are pricier than the equivalent effect would be in white or green, but mana is not an issue when your commander is a machine that turns copies of Brute ForceBrute Force into Dark RitualsDark Rituals
The commanders of each deck are, of course, the central protagonists of each game, with Terra, Cloud, Tidus, and Y'shtola all featuring
There are multiple ways to build the deck too, with Arcades, the Strategist being an excellent alternative to Doran as commander