The first two modes are always eligible to be chosen
For the two metal balls, you throw them down a plastic ramp in the middle of the accessories container
Its most popular in Baba Lysaga, Night Witch decks, because it satisfies two of the three needed card types to trigger that commanders ability, but we also see it in lands-matter decks, like Jyoti, Moag Ancient and Jolrael, Voice of Zhalfir
For decks with three or more colors, where you might only be able to afford a small number of MDFCs since you'll need most of your lands to either be basics (for ramping / tutoring purposes) or tap for multiple colors of mana, the best MDFCs are Bala Ged Recovery (seriously, if you have green mana in your deck, play this card), Valakut Awakening, Hagra Mauling, and Ondu Inversion, along with the mythic cycle, which is almost always good if you can afford another land that only taps for a single color of mana
However, I'm mostly excited about Renegade Rallier not as a value card but as a combo piece
If that power was 0 or less, Juri deals no damage