BlockFi is an interesting passive annuity platform. Unlike Compound, for example, it is a centralized platform with large (and reliable) companies such as Gemini, Fidelity and investors of the caliber of Akuna Capital behind it. BlockFi is an online wallet that allows you to earn interest simply by depositing cryptocurrencies.

What are the cryptocurrencies supported? Bitcoin, Ether, Gemini Dollar, PAX, Litecoin, USDC and USD (as stablecoin).
Variable interests are received on these cryptocurrencies. Once the cryptocurrencies are deposited, interest begins to be earned (the balance is updated day after day and paid at the end of the month). Interest is paid in cryptocurrencies and not in stablecoin (this is an important thing to understand). Obviously you can withdraw them at any time without any restrictions.   As can be seen from the table, these are very high interests (especially for Bitcoin). Is there to trust? Absolutely yes because the cryptographic assets are kept at Gemini. This third custodian has excellent insurance and an excellent track record with no loss of customer funds. In fact, Gemini collaborates with many loan services and other cryptocurrency sites. Other interesting functions are those of Trading and Loan. 🆃🆁🅰🅳🅸🅽🅶 allows you to seamlessly manage your cryptoassets and optimize your portfolio allocation. As regards the "𝕃𝕠𝕒𝕟" function, it is possible to choose as collateral: BTC, Ether & Litecoin. The platform also features an interesting 𝙧𝙚𝙛𝙚𝙧𝙧𝙖𝙡 𝙨𝙮𝙨𝙩𝙚𝙢.
For each new friend who signs up using their unique reference code and deposits $ 100 + of cryptocurrencies into their BlockFi account, you and your friend will each earn a $ 10 bonus in BTC. Your friend will need to hold the balance until the next interest payment day to qualify you both for the bonus.
After 5 valid submissions, you will start earning a $ 20 bonus (your invited friends always $ 10 though).  

To sign up: BlockFi (Signing Up)