What aspects of OpenZeppelin are free to use?

I’m new to smart contract development and was wondering what parts of OpenZeppelin are free to use. I’m currently going through the upgradeable smart contract tutorial with Hardhat and was wondering if this is free in production or just the testnet. What other aspects are paid/free?

I think current productions have:

And almost all are free. I only know asking OpenZeppelin to audit contracts needs to pay.

Great, thanks a lot!

Defender is free for individuals.