Sure, throughout the cryptocurrency space there are plenty of opportunities that can earn longterm, passive income. An example would be Rentberry – Long-term apartment rentals, which is a tech startup in the rental property space that uses blockchain technology and high transparency between landlords and tenants in order to create a new type of ecosystem for renting in the US.
Specific to your question, token holders will soon be able to earn a passive income of roughly 7% by crowdfunding the security deposits of renters. Afaik this is the only instance of this model being used - I’ve never heard of another way to crowdsource security deposits, let alone in a way that incentivises all 3 parties (renter, landlords, token holders) at the same time.
If you’re making roughly $15k per month and over the course of a year you were collecting 7% from crowdfunding tenants’ security deposits.. I’d imagine that would end up being enough of a monthly income alone after 1 year of earning from the interest on crowdfunding loans.
If you’re interested in discussing further details of the Rentberry project with the team or any of the supporters who are in similar situations to yourself then there’s a strong community at Rentberry ICO