Theyre useful for players who look to test new decks or cards and want in on a fantastic format without blowing a ton of money, buying budget EDH decks, or scraping by with a $20 Commander deck
Standard was where the money came from, as its the format people needed new cards for
Following a Promising Lead to a bookcase covered in ley lines, they reveal the secret entrance after pulling a specific book marked on a torn page
If your game plan is to flood the board with tokens, Rhys is a ridiculous pick hes the best Elf commander in MTG for that style thanks to his one-mana cost and board-doubling power
Opal has had a particularly strong showing, notably appearing in several artifact stuffed lists that aim to win the game with a kitted-out Kappa Cannoneer, while Green Sun's Zenith showed up in a modified Yawgmoth list, as well as an Elementals deck running Omnath and Risen Reef
As for something more dedicated, Id check out Sam Blacks Five-Color Niv-Mizzet Reborn / Bring to Light snow deck