The Zendikar block had an interesting cycle of Quest enchantments. While the Quest for the Holy Relic is not by far the best of them, it’s an interesting card. This Quest only costs 1 white mana to cast. Whenever you cast a creature spell, you get to put a quest counter on the Quest. Once it has at least five quest counters, you may sacrifice it. When you do so, you search your deck for an Equipment card and put it onto the battlefield attached to a creature you control. You then, of course, shuffle your library.

There are certainly equipment-based Commander decks that love this card. These include decks that rely on their Commander beefed up with multiple Equipments swinging in for Commander damage. The Commanders that utilize this one-mana Enchantment the most include Kemba, Kha Regent and Nahiri, the Lithomancer.

While it’s not the most efficient tutor for Equipments, Quest for the Holy Relic is cheap to cast and fairly easy to trigger. It’s an investment of only one mana, and it gets you an Equipment onto the board and attached to a creature for that minimal investment. Any Equipment-based deck in Commander that runs White should at least consider it. Heck, Quest for the Holy Relic has even seen occasional play in Modern. It's a good card, but its effect is usually a bit slow to develop for Modern. Still, Quest decks were fun back when it was legal in Standard, and they're still fun to build and play.