I've had great success with different varieties of pothos and tillandsias in my gecko terrariums. I've grown some different ferns as well, including a staghorn fern I have growing in my gargoyle gecko terrarium. It's seemed quite happy.
I've had a few peperomias and scheffleras do well in them too. The scheffleras will require some height though. These were growing in terrariums with lower humidity than yours though, so may not be the best option.
Bromeliads are great for frogs too. They have tough leaves that can support the weight of small animals resting on them, and frogs like resting in the central vase where water collects (in the wild, they'll use them to rear tadpoles).
Some other good options for dart frog setups are:
- Syngoniums
- Spathiphyllum
- Some philodendrons if you have a larger setup
- Orchids
- For Bromeliads, Neoregelia in particular are a good option for terrariums.
- Anthuriums
- Most ferns (ex. Rabbit's foot, bird's nest...)
- Selaginella
- A variety of moss species. They tend to do well in high humidity setups. I've found them a little tricky to maintain though.
