Grist simultaneously being a powerful midrange threat and a card that can be cheated into play means that it has lots of room to be incorporated into current or future Modern archetypes
3 Tinker Bell, Giant Fairy Smashing The Competition Tinker Bell may be small, but Shifting her into Tinker Bell, Giant Fairy will make your opponent think twice about messing with this Fairy
DOMINARIA UNITED: RED Multi-Chaos Warp is a good magic card, especially for mono-red decks without answers for many card types
The alternate commander for the Elven Council deck is Radagast, Wizard of Wilds, who, through his love of nature, can turn your five mana or more creature spells into bonus Bird or Beast tokens
As I suggested with Illuna, The Ozolith might have some game here as well
Mono Reds creatures are too fast to be vulnerable to Vapor Snag and Mana Leak