Long story short: a lot of the "fun" of making a terrarium is some trial and error; you may need to try a few different plants out in your terrarium before you find the right plant for your container.
Where to start? Here is a list of frequently recommended plants for terrariums.
African Violets have a reputation for being finicky, but also may be a plant suited for terrarium life. Proceed with caution and follow all instructions for care of violets.
Baby's Tears or Soleirolia
A small plant with delicate leaves on short stocks. Baby's Tears can become invasive given proper growing conditions- you may need to pinch it off.
Begonias are a diverse group of tropical flowers that love humid and moist conditions, and some of them prefer low light as well. Look for compact varieties or plan on pruning.
Small bromeliads can thrive in humid terrariums.
Club Mosses were historically grouped along with Spike Mosses, but are now recognized as separate classes.
Dracena is a shrub-like houseplant, probably too large for most terrariums. "Lucky" bamboo is a dracaena species!
Ferns thrive in a variety of climates. Look for smaller ferns as most do not like having the fronds press against glass.
Another popular houseplant with variegated leaves, Fittonia has a reputation of being difficult to grow. Can grow as a ground cover.
Hypoestes or Polka Dot Plant
Compact plant with variegated foliage in pink, silver or red varieties. Hypoestes enjoys bright, indirect light. May need to be pinched back if they get too spindly.
Ivy or Hedera
Ivy makes a great terrarium plant when managed carefully. Look for small varieties.
Orchids might be the unicorn of terrarium plants. Everyone wants one but it can be difficult to find the right orchid for a terrarium, and the right terrarium container for an orchid. Read more about orchid terrariums.
There are many varieties of peperomia, with a large variation among leaf size and shape. Prefer low to bright indirect light.
Pilea or Aluminum Plants
Pilea like low to medium light and warm temperatures. The leaves show veined white markings. This plant grows fairly quickly, so you may have to pinch it back occasionally. Aluminum plant is easy to root, just by taking a small cutting and planting it in moist soil.
Prayer Plant or Maranta
With chevron patterned leaves, Prayer Plant enjoys warm temperatures and medium, indirect light.
Spider Plant or Chlorophytum
Spider Plants grow in a rosette pattern, sending out spear shaped leaves. They are easy to grown in nearly any condition but may outgrow their terrarium.
Long stems with spade-like leaves. There is evidence that spiderwort performs well in bottle terrariums.
Spike Mosses or Selaginella
A little bit like moss and a little bit like a fern, spike mosses look perfectly at home in a terrarium. Many varieties available.
Succulents prefer sandy soil, infrequent water and bright sun. Do not plant succulents alongside moss - you'll never keep both happy!
Zebra Plant or Aphelandra
Zebra Plant or Aphelandra is a common houseplant in North America. They may outgrow a small terrarium.