Here is the list of top 5 safe sites where you can download APK files for free in PC/Mobile without signing in playstore.
The best site to download APK files for free. Click here to start APK Mirror
Lots of APKs available in this site and you must try it. APK 4 FUN
3. APK Pure
An another best site to download APK files for free. APK Pure
Not as best as above three. But it has number of apps and games BlackMart
5. Android Free Download
Best sites for gamer especially, you should try it Androidfreedownload