There are cards like Famfrit, the Darkening Cloud [3-123R], who does not choose its target, but many cards that are used to defeat a Forward will have to choose Neo Exdeath [12-110L]
Wake Thrasher Wake Thrasher ($0.65) is meant for Merfolk Tribal usually but that does not mean it isn't good for other decks
Its still a deck I find myself returning to because its remarkably easy to play, and while Atarka, World Render is hardly a pricey Commander, there are still some slightly pricier cards to be found, like Scourge of Valkas and Dragon Tempest
This creature benefits from aggressive mana ramp, and if Elvish Archdruid is around, then paying a lot of mana into each X cost should be easy
It is the same problem that I see with cards like Violent Outburst or Ephemerate: They do nothing on their own
Emeria Shepherd ( Battle for Zendikar ) Despite being pretty expensive to cast, Emeria Shepherd might have one of the best landfall abilities of all time