What about file DPI
The legendary artifact card that jumps to mind for me is of course Excalibur, which will circumvent that pesky high mana value, but there are a ton of sweet options you could put in the deck outside of Equipment
However, it comes with the ability 10,000 Needles, which makes it gain +9,999 power until the end of the turn whenever it attacks
Explore mechanics are most commonly found in blue and green, making it a natural fit to build a Merfolk deck around
Since everyone needs at least one creature out to keep Sothera around, youre encouraged to use it more as a grindy value tool than a continuous board wipe
Rally at the Hornburg often outshines Shadow Summoning, but in the games where flying is relevant, the difference is remarkable