When you download a trial version of a Chaos product that includes Chaos Cosmos, you get access to the Cosmos asset library.
Please keep in mind that the trial license comes with a curated selection of assets, which is more limited than what's available in a full subscription. To explore the specific assets included with different products and plans, feel free to visit the official Chaos Cosmos website.
You might also be interested in seeing which Chaos products support the Chaos Cosmos asset library: