They make a great terrarium for air plants. With a few other items they really look good. Air plants are great for this because they don't have to be watered but once a week and you take the plant out and soak it in filtered water. So no water goes into the tealight holder.
For the one pictured here we used air plants, colored moss, and some rocks. You just place them all inside in a way that you think looks nice.
You can get these tealight holders on Amazon here. The moss, rocks and air plants we got through Makerskit. This is a great company that even has a subscription box where they will send you some sort of craft kit to make at home. It's not very expensive and they have been pretty neat so far.
All in all, I really like these tealight holders. They have so many different purposes that all of them will come in handy. These come in a set of 4 so it's great for many different crafts.
Have a great day!