I have seen some really cool projects like cryptoknitties and crypties with rarity levels and they usually come in like 5-10k. I have some great ideas but I can't find anywhere to learn how to do this on the internet or Cardano website? Are there any resources available to learn how to do Cardano NFTs like that?
You can use this tool to create native tokens or NFTs: https://cardano-native-token.com This is the easiest userfriendly way at the moment. It's required to have more technical skills if you want to make more complicate NFT setup.
There's nothing particularly built into Cardano that provides this functionality. You would personally control releases. If you want to mint a single item, do that. If you want to mint 100, do that. Of course as the amount rises, the less convenient it is to do this manually. I imagine anyone that's doing this with any level of seriousness is also writing a stack of custom tools to manage the process from creation through sales.
Eventually there will be marketplaces available that will do a lot of this for you; for a service fee, of course.