Owner financing, financing that is based on value and not based on purchase price, lease options, etc.There are also entire books written on how to extract sweat equity such as BRRRR, leveraging under utilized zoning, parcel plits, etc. 

I have it for Las Vegas because I wrote software to extract the information.However, you can get a reasonable feel for rental trends based on price trends.

Our motivated seller leads go through a 2-step process: (1) they enter our digital funnel and fill out a form to be contacted about receiving a cash offer; (2) we then phone-screen the homeowner to extract additional information.

I'd rather live in an area where everyone can agree that if given an alternative, that kind of result does not benefit ANYONE (except perhaps the landlord who extracted value from the community for years and years). 

My goal is to move out of this duplex eventually in a few years and rent the other side out to extract the most cash flow possible.

You can also extract it from public records.

If you're looking to extract more than a few grand, you're looking for too much.

I believe it's because many landlords want to passively extract money for communities and don’t want to contribute their pro-rata share towards advocating for the neighborhood.

Hire a talented manager and make sure that you're extracting maximum revenue from the remaining holdings. 

If so, sometimes condos can be challenging as investor owners often don't want to do upgrades and updates, many just want to run the property into the ground and extract as much cash as they can get today, without thought to the future.