How would I research this online? Looking for an address in the heights from the 50s

My grandparents lived in the heights for a time in the 40s and 50s and I’d love to find their address.

I had hoped the 1950 census would help but it doesn’t seem as if it’s complete because I absolutely can not find them on it.

Years ago I did find them in a phone book from the era at the library down in Galveston but I’d love to be able to find their address online rather than make that trek to Galveston (or any library for that matter)

I do have access to Houston public library’s archives but I can’t seem to find what I’m looking for there either but I have a feeling it’s simply an issue with me not know what to actually search for.

So any ideas on how I can find the info?