The Thrive Content Library (TCL) is a collection of all saved content in the game. It contains literally everything a player needs to build anything they like. It contains every evolutionary form of every one of their controlled species, every TO they make, every solar system their species inhabits. It will not automatically update, but players can add to it in various ways.
Not all organisms in the game will be saved to the TCL. Only organisms that you have played as, downloaded or have given names in the game will appear, with the exception of fossilized organisms. A -player can sort organisms by size, biome(s), diet, colors, body type, template organism, etc.
Tech objects will work just like organisms, but can be searched by different parameters.
Nations refer to organisms that have a culture created in the culture editor. Races must be saved with their solar systems, because their culture is heavily dependent on their surroundings. They otherwise work like TOs and Orgs.
Planets, set up by topography and biome placement can be saved and downloaded individually, and then repopulated in the game. They can also be saved with all of their known life, although this is an extremely large undertaking to download later.