Ultimately, Mew ex is clearly best utilized against decks that heavily rely on other strong ex cards , as those attacks are some of the strongest in the entire game, meaning that players should absolutely take advantage of them whenever possible
In a private game, you'll just have to put up with your friends harassing you
Some other random goodies you might like: Maddening Hex (this would be HILARIOUS with some doublers), Chandra's Ignition (if you target something with lifelink remember it's the CREATURE doing the damage, so you can gain a TON of life off of this if the board is fairly full, and it's great with a Deathtouch source like Gift of Doom), Fire Covenant (one of the best burn spells ever), and MAYBE a Rionya, Fire Dancer since you've got all those Sorceries
Im talking about lore wise here Hades is literally Looking for a Deal as the card title suggests, whereas Ariels card may be hinting at the ill-informed deal she made with Ursula
The playful line work and Mews content expression as it holds its tummy evoke the happiest of vibes