As you may know, App Grid is a lightweight, closed source but free alternative for the Ubuntu Software Center. It has a modern and intuitive graphical user interface, offering a grid view of the installable applications, including screenshots and ratings.
The latest version available is App Grid 0.252, which has been recently released, coming with a bunch of changes only.
Up to date packages are available via some third party PPA, so installing the software on Ubuntu 18.10 Cosmic Cuttlefish, Ubuntu 18.04 Bionic Beaver, Linux Mint, Elementary OS and other derivative systems is easy. All you need to do is add the PPA to your system, update the local repository index and install the appgrid package:
$ sudo add-apt-repository ppa:appgrid/stable
$ sudo apt-get update
$ sudo apt-get install appgrid
Optional, to remove appgrid, do:
$ sudo apt-get remove appgrid