All Creature Cards in the game belong to one of the game's six factions. All except for Rainbow (which can be placed on any one of your Landscapes), they can only be placed on their respective Landscapes. Cards are marked for their Factions using colored borders and also symbols in the top right corner, e.g. a yellow border and an ear of corn for Cornfields. Rainbow is a unique faction, as not only are their Rainbow Creature Cards, but all other cards i.e. Spells and Buildings, are also classified as belonging to the Rainbow Faction. Not only does this mean they can all be placed or cast on any Landscape, but it also means that in Quests in which you must only use Rainbow Cards, you can use Spells and Buildings too. Factions are not different in only their coloring - Creatures in the same Faction normally have similarities in their Stats, Floop abilities and also appearances.
Cornfields: These green-yellow creatures focus more on attack than defense most of the time, and have attack-oriented floops (i.e. Husker Worm and the Cornball).
Useless Swamp: These red-green creatures have high attack and typically low defense, and damaging floops (i.e. Mace Stump).
Sandylands: These brown creatures normally have higher defense than they do attack, as well as defense-oriented floops (such as the Sandfoot)
Nicelands: Most of these bright-colored creatures are defensive and have healing floops that heal themselves, other creatures, or even your Hero (i.e. Blueberry Djini).
Blue Plains: These blue creatures are typically defensive and have floops that can't really fit into any of the other categories (i.e. Cool Dog).
Rainbow creatures fit in any landscape and have floops from other categories, but have half the stats of other creatures in their rarity. (i.e. Mouthball and The Pig).