Where do you find the house listing information and rent estimates

[Zhen Yuan]

Hello,

I am a newbie in the real estate area and want to ask where to find a potential house for sale information.  I only use Zillow but want to ask is a more comprehensive listing that I can access (for example, which is the preferred source for foreclosure homes). 

Also, I want to ask how to estimate the rent for deal analysis. I know that Zillow sometimes has estimates and BiggerPockets has an estimation tool. Other than that, do you know what other tool I can use? Thanks.