I'm gathering information about landlord laws. What are some of the basics that you are interested in? Thinks like "how long do you have to return the security deposit?"
I'd say the one that could get you into trouble quickly is discrimination.
One I'd like to know about is whether I can sell my property with a tenant in it or not. If I sell to an owner-occupant will the current lease be cancelled or do I have to honor the lease by transferring to a new owner or maintaining ownership?
All of them! It's the ones that you don't know that can cost you.
Discrimination laws would certainly be important.
Eviction laws and processes
What constitutes habitability? (ie, what am I legally required to fix?)
What can I put in a lease?
Pets, service animals and emotional support animals, oh my!
What damages can I charge my tenant for? (Or what's normal wear and tear?)