I personally use propwire.com for residential lists but you can get them online from tons of places. 

Look online to see if any properties are being offered for sale or rent with a legal basement unit and you may get a tip off.

The following details matter when asking this question and you didn't provide them: Level of participationREPS or notType of property (short-term, long-term)Since you didn't provide them, it look Austin Cheatham answered the question assuming long-term, and didn't take the other factors into consideration.

At the end of the day, it's just a matter of who is willing to give you a better deal and has the flexibility to do so.

If that matters.

Look for parks, schools, groceries, and local hangouts—these things matter!

Send a letter giving them your/pm's contact and a detailed explanation on how to pay the rent (Helpful with older residents if you are going from check to online billing.

I typically use regional banks to fund my deals but my 2 go-to banks have either slowed or fully stopped investment loans so recently I've connected with several online brokers but all came from ads or they reached out to me vs personal recommendations and intros so I have concerns. 

Lots of material online.  

If you are listing it online, aren't you just in a sense just "listing it on market"?