Elastic bands always bruise the rim of the card and leaving them loose within a larger container risks your deck getting mixed out of order
The end result is a bizarre mash-up of the two games, with an early style of Blastoise being printed onto a Magic the Gathering card backing
Conkeldurr is classified as a 3-Diamonds card in the Celestial Guardians set
While the "ease of flipping" category is, in large part, a product of the number of defense counters on the battle (battles range from three to seven defense counters, and a battle with three defense counters will be much easier to flip than one with seven), it also takes other factors into consideration, like whether the battle makes creatures (if so, we can use them to help defeat the battle, making it easier to flip) or whether the battle acts as removal (which can get a blocker out of the way, making it easier to attack and defeat the battle)
Id love to see it happen, but I just dont think its likely
Dragonlord Atarka is the biggest one, and a nice reanimation target, splitting up 5 damage on ETB