A space hound, got me i would think said person would be a rock hound that has a limit set on the types of material that collect dust in the house that is on display.
A catapultist.
onithbfdbvb
I would call him a hobbyist.
dumb
A button collector??
normally .you call one .a letterologist.
a hoarder x)
Graphologist comes to mind or autograph hunter.
Someone with too much time on their hands and too much space?
An aquarist is someone who collects fish in aquariums. They can also simply be called fish keepers. Some collect a variety of fish, while others specialize in a few kinds.
An Arctophile.
A key enthusiast is one way to identify them. There is no actual term to refer to someone who collects keys out of enjoyment, but if they keep the keys out of fear that they may find a use for them after throwing them away, they are potentially a compulsive hoarder.