What you choose for plants should be something the frogs will use. Small bromeliads in the cup coming out at an angle would be good. Bromeliads hold water and need no soil to grow. Most of the root can be removed and then placed just about anywhere as long as the center can fill with water.
Cryptanthus also goes good with dart frogs and comes in many colors. I would have this grow up out of the soil straight up so it creates something to climb on and hide under.


More cool accents are:
Monkey Pods hold some moisture and when place on their side so sunk into the soil at an angle provide places for the dart frogs to hide.
Live Oak Leave Liter retains water like little cups, gives the frogs things to climb under, and looks great. You just leave it in the tank and let it rot away and when needed, pile more on.

If your doing darts, I like the Leucs as a starter. Keep in mind that your going to want to cover the top completely for darts to keep humidity at 90 percent and higher. With darts you also want to keep temp in the day around 76 to 82 degrees and never 85 or higher.