Your first mana activation for an artifact each turn is reduced by two, and that works on your foe's turns as well which ramps up with more foes in multiplayer
Tapping an untapped creature that's attacking or blocking to pay a teamwork cost won't cause that creature to stop attacking or blocking
Recently, Wizards of the Coast released card spoilers for Theros Beyond Death (see "Wizards of the Coast Previews 'Magic The Gathering' 'Theros Beyond Death'")
Market price $0.28 Based on the latest market prices tracked on TCG Stacked
Leylines are also easy permanents to get into play if they're in your opening hand, and most of them add to your devotion count, which can supercharge the mana you get from Nykthos, Shrine to Nyx earlier than normal
In my experience, this card does a ton of work, and I like that it can come out turn one and get to business