An arts and crafts based rider whose collectibles are crayons, pencils, markers and paints and weapons are scissors, rulers, glue, stapleguns and brushes. Ultimate weapon is an easel and paint palette. Obviously a starving art student that's trying to gain the fancy of a senior at his uni.
Secondary is an origami rider with obviously origami paper as collectibles and needs to transform by offering up origami to his talking art critic belt. His power-up is achieved by mix and matching complex origami animals. A kindergarten teacher whose identity is publicly known and is only doing this because his kids would be disappointed in him if he stops.
Monsters are born out of paintings and the main antagonist is an avant garde frenchman painter that looks down on anything that aren't oil paintings and is out to hunt down legendary pieces by the man who is the source of the painting monsters