I don't expect it to be implemented but just a strange idea that I came up with for a trade resource on planets.
Might be interesting to have a very rare trade resource on a planet, kinda like an evil corrupted growing plant or something. That slowly spreads each 20 turns to one new tile next to it on the planet if its empty. Maybe it can give you 1 ideology point every 40 turns per plant you have and minus approval on the planet. Could have a good and natural version to lol. And if you don't like them you can still destroy them as you can every other trade resource on a planet. Maybe they would be op and would need to have the turns changed, but wanted to share my idea 