You never want to choose more than three colours (at least, most of the time) and if you want to be safe then having two is probably the best way
And we both whooped with joy at pulling the adorable Galarian Gallery Ditto, disguised as a grinning Numel
So anyway, with only four Arid Mesas, Knight of the Reliquary will probably start off as only a 2/2 (maybe a 3/3), but will only rarely get serious in size ahead of time
Its not hard to include in many other decks but often wont do much either
If everyone is trying to go fast and win the game, getting rid of creatures that cost less than this three mana spell is a recipe for disaster
Sol Ring is the card you find most often, but theres a bevy of powerful artifacts this can search for including Skullclamp, Sensei's Divining Top, and Mana Vault