Cross-galaxy teleportation macguffins. The Delta quadrant. Where are the Borg!?
The Kazon, aka less-good, less-organized Klingons. Were Klingons racist? Or the Ferengi? Or the Kazons?
The availability of water in star systems. Exoplanet surveys and water-rich gas giants.
Yay Janeway! Comparing with the original actress. Imagining a Star Trek/Too Many Cooks crossover.
Replicators and teleporters
The most incredible Star Trek technology of all. Teleporter failure rates: very low, or actually 100%?