I started to grow the Ruellia repens weed too, with the same intention of one day trying it out as a terrarium plant. Unfortunately, I don't think it is a good choice because the flowers last a day only. In a container, it would probably shed the flowers which would rot in the soil.
I also recently bought the white and pink leaved Hypoestes phyllostachya (Common Name: Polka Dot Plant, Freckle Face; Family: Acanthaceae) and I am stil considering whether to grow it as a terrarium plant.
Finally, the last 2 photos were taken of the Brugmansia cutting that I successfully propagated. Well, one of the cuttings didn't make it after I transplanted it out, presumably because the cutting was newly rooted. The remaining one is still growing well but I agreed to give it to a friend.