Cats and Phyrexians
Balefire Dragon's effect doesn't look at its base stats, so when combined with other cards that boost stats, it's not uncommon for Balefire Dragon to lead to full, one-sided board wipes
Merrow ReejereyMerrow Reejerey brings the heat as a 2/2 for (requiring only one pip makes a difference) that, as lords do, boosts your other Merfolk by +1/+1
set are legal in these side events, though not in the main tournament
You only need three artifacts in play to enable that, which sounds imminently possible
For one mana, you have a card that can buy you time, combo with Valki, or be a weak way to trigger your enters-the-battlefield effects