Yep I don't know how I didn't think if this, I use Google always to find whatever files like videos and mp3's and I tried to find Android APK files and it worked very well.
To find and download APK files easly "Android Package" which most applications comes packed in just type this in Google or simply click it right now "-inurl:htm -inurl:html -inurl:asp intitle:"index of" +(apk)".
This is simply searching directories holding files with APK extension which website owners didn't care to protect using an index.html file or .htaccess anti directory listing.
Enjoy downloading, if you find it hard to memorize just type "Download android APK google hack" on Google, access this page and click the link.
You will find stuff that ain't on the market because of your region or network.