Estinien has loads of interesting things going on, from getting aggressive with a leader you can send in the air to incentivizing both non-creature spells and dragons
If we flip it and take a closer look It looks like Ursulas Lair opening its jaws, with the outlines of what might be an Amber character in the missing chunk
Shapeshifters with Changeling are vampires, soldiers, humans, slivers, and much more, benefitting from everything that helps those creatures
If Clever Impersonator enters the battlefield as a copy of a planeswalker, it will enter the battlefield with a number of loyalty counters on it equal to the loyalty printed in the lower right corner of the planeswalker card
And you can bet plenty of creatures will be coming your way if you decide to rock the new Toxic mechanic
As Flamewar, Brash Veteran, you can sacrifice an artifact to put a +1/+1 counter on it and flip it