Like creatures and enchantments, they hang around on the field after being cast, can have static, triggered, or activated abilities, and tend to die to removal
Basic lands, Foreign, or silver/gold bordered cards
2 Kurbis, Harvest Celebrant Despite its sinister appearance, Kurbis is actually one of the more nurturing Treefolk commanders out there, with abilities that focus purely on protecting your other creatures from harm
They are played to your board using their ink cost
Ultima, Origin of Oblivion lets you use Forsaken Monument as your Commander, which is kinda cool
The Cabbage Merchant The Cabbage Merchant generates a lot of Food tokens during the course of a game based on the spells your opponents cast