Not sure if anyone has said this yet, but I would love to see a few ephemera based around certain elements; space, paw prints, feathers, and the Sentients!
Similar to the cosmic dust decoration for the dojo, it would have a galaxy-like effect. Crafting Requirements: Nova Systems.
Paw Print Ephemera
An ephemera that leaves a small trail of paw prints behind your Warframe! Valkitties unite! Crafting Requirements: Valkyr Systems.
An ephemera that leaves a dancing trail of falling feathers behind your Warframe. Crafting Requirements: Zephyr Systems.
An ephemera that adds Sentient-like tendrils to your Warframe(similar to the ever lovely Limbo Deluxe skin) and fiery, wispy energy it is affect by your health. The more you have, the brighter they glow—the less you have the dimmer it becomes. Crafting Requirements: Revenant Systems.