Where to check for lost pets?

Hello, I've lost my cat 2 days ago and I've walked around my apartment complex twice already to look for him but no luck. I've printed out flyers and will be taping those around today. In the meantime, I want to check out shelters as maybe someone surrendered him. I live near the willowbrook mall. I'm just not sure where to start looking. Here are the spots I will check out: Special Pals, Houston Pets Alive(Google says they're only open on Saturdays), and Houston SPCA.

If there are other places/shelters I should check, please let me know.