@Saiqal Khan
There are plenty of South Side/South Suburbs/NW Indiana that have 30-50k properties. As other posts mentioned, they may not be worth the effort. Without having a better idea of your goal, our answers may be incomplete.
-Are you trying to wholesale properties? Fix and Flip?
-Are you trying to get cheap properties, fix them up, then rent them out?
-How are you paying for these properties? Cash or financing? At that price point, you may not be able to do conventional financing.
As someone who has South Suburban property, yes, lower priced areas like Riverdale/Markham/Dolton can be block by block (not unlike inside Chicago neighborhoods). Also your taxes can vary. They will be more than Chicago. Sometimes a little, sometimes much more.
I think finding good tenants is an issue for plenty of landlords regardless of area. That being said, if property is rehabbed well, in quiet area, etc. you should be able to find someone.
Also each city has different rules for landlords. Some may not care, others basically require a yearly fee/license paid to the city. I believe South Holland has frozen the number of licenses, so investor would have to buy property from an existing landlord in order to not get in trouble with the city.
Hope this helps.