Some projects have their own, customized marketplaces so that you can engage with and purchase NFTs directly from their site. You may be interested in a specific project or collection and this way you can find out all of the details about the project and narrow down your search.
1. Hover over the "Explore" button on the top of Rarible's home page and then click on "Marketplaces."
2. On the left-hand side of the explore page, you'll find filter options. Click on the blockchain that suits your wallet and that you're interested in discovering. You can also use the search bar to find the collection.
3. Click on the collection that you like.
4. You'll be converted to the project's marketplace where you can find out more about their collection/s and buy their NFTs.
For example:
Note: You can learn more about marketplaces and how you can create your own marketplace by reading these articles: What is a community marketplace? & How do I create a community marketplace?