1X Tiles

Used for regular app listings

Builder
IDE for GNOME
Documents
Manage your local and online documents
Peek
Short screencapture software that outputs GIF images
Gedit
text editor
Photos
Access, organize and share your photos
Polari
IRC chat client
GNU Image Manipulation Program
Create images and edit photographs
Music
Play and organize your music collection
Inkscape
Create and edit Scalable Vector Graphics images
Blender
Open Source 3D creation
Boxes
Simple remote and virtual machines
Transmission
Download and share files over BitTorrent

2X Tiles

Used for featured apps and addons and fonts.

Builder
IDE for GNOME
Documents
Manage your local and online documents
Peek
Short screencapture software that outputs GIF images