I installed a few apk files for applications and now the icons won't go away from the Launchpad on my Mac.
Is there a file, database or some other location where these are stored?
This isn't exactly my area of expertise, but Chrome is automatically installing icons for apps any Chrome apps you have installed through it.
First Visit chrome://apps, find the app, right click, then "Remove from Chrome".
Next, if the app icons are still showing up in your launcher, it sounds like you need to open the folder "/Users/[your-user-name]/Applications/Chrome Apps" and delete the icons from there that you no longer want.
If you do not remove the apps from Chrome first, the launch pad icons may get recreated the next time you start the browser.