Section 8 is a searchable field in the HAR.com home search section titled "Find a Rental" . Within the search page of Find a Rental choose section 8 from the choices in the drop down menus under lease terms.
First try "Find a Rental" on HAR.COM. Look in the Lease Terms category. There is a dropbox link for Section 8. I agree there aren't many to choose from.
If that doesn't work try totalmoveintx.com. It is a locater company. Good luck to you!