Google Photos has a search page that shows a few filters: Creations (replaces Auto Awesome), Google Drive, Video, Recently Added. Here are some searches you can use to bring back the filters from Google+ Photos:
#AutoBackup - shows all the photos automatically backed up from your mobile devices and desktop computers
#Desktop - shows the photos automatically backed up from your desktop computers
#Posts - shows the photos added to your Google+ posts
#All - shows all your photos
#PhotosOfYou - photos you've been tagged in
#CAMERANAME - replace CAMERANAME with the your camera's model or brand to see all the photos taken with that camera. Some examples: #Nexus5, #Canon, #iPhone.