mtg cards like guttersnipe - Magic #LB this creature deals 2 damage to each opponent. HOU][CUBE] Firebrand Archer - Cube

Find groups that have lots of followers, strict rules and that are private (my preference.) A good example of a really good Facebook group that I think is one of the more popular places to sell Magic cards is MTG Savage Sales (Magic: The Gathering.) They have over 12K members and the admins do a great job making sure the rules are being followed

Instant speed, uncounterable and equipped with self-protection

When you attack, you have a guaranteed damage trigger that also exiles

If you target a single player you'll likley be targetted by the other two before you can accumulate an insurmountable health pool

Not that thats a bad thing, of course

As you're limited by colors here, Sidisi seems more likely to find a spot in the 99 than as a commander in her own right, but she's going to fit into a ton of decks