Is it possible to reset launchpad layout?
To reset Launchpad to the default, delete the following file:

/Users/$USER/Library/Application Support/Dock/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.db



Where "xxxx..." in the file name is an alphanumeric string.


And then run the following command in a Terminal:

 killall Dock


The Launchpad is now reset to the default and a new database (.db file) will be created with the default settings.

Note:  If you want to examine the contents of the database you can use an app like Liya.