Getting upside for simply playing the game has historically led to some very powerful cards (see our previous discussion regarding Tarmogoyf), and Ill be very surprised if this ends up as an exception to the rule
You can care about the toughness of the creatures, or care about defender tribal
Battle at the Big Bridge (Fatal Push) and Thrum of the Vestige (Lightning Bolt) are the easiest to fit, in my opinion, as well as Zidane Tribal (Ragavan, Nimble Pilferer), which will play in any deck that has red
Intellectual Property Disclaimer
If your Commander deck has two commanders, you can include only cards whose own color identities are also found in your commanders' combined color identities
One offering to appease her on her arrival