Hi, this is a great question! Yes, RocketBot is a fantastic option. On the flip side, you can also try out the Wallet Plug-in with Subscriptions.

Follow the FunC code here: https://github.com/ton-blockchain/wallet-contract/blob/main/func/simple-subscription-plugin.fc

It's a general-purpose subscription contract that you can use in many scenarios. For example, people can deposit and stake on-chain in this contract, and then you can receive a subset of the monthly income transferred to this subscription contract.

I'm not aware of one from a smart contract perspective, though it could be a very cool idea.

TON Rocket Pay has a few services which might be what you're looking for:
https://pay.ton-rocket.com/api/#/subscriptions