You rarely see them left out of decks in their colours
SR Super Rare Mimicking Man-Eater Bug X EARTH Level 4 [ InsectFlipEffect ] ATK 450 DEF 600 FLIP: Target 1 monster on the field
But I do think that varying your approach to where you're, not just spending time playing games, but also looking at other aspects of how other people play the game helps for a more holistic improvement
For Deck building, there are a couple of directions you could go in to make the most of this Skill, we would recommend trying to keep a balance of Harpie and Amazoness monsters to improve the odds that you can use your Skill on the very first turn and begin setting up to get the second effect
If you need a primer on this, check out our how to use double-faced cards in Magic: The Gathering article
Physical GameStop, Target, Walmart, and Best Buy stores may also have the Holiday Calendar on shelves, as may any local game store that normally offers Pokmon cards