Download any debloated custom ROM, unzip it and compare to the official one. Look in /system/app and /system/priv-app folders - any missing apk is safe to delete (or freeze, if you are not sure).
ANT Radio
ANT+ Plugins
AT&T FamilyMap
AT&T Hot Spots
AT&T Locker
AT&T Messages
AT&T Mobile Locate
AT&T Navigator
Beats Music
BlurbCheckout
Business card recognition
Caller Name ID
ChatON
Device Help
DriveMode
Flipboard
Google Play Books
Google Play Games
Google Play Movies & TV
Google Play Music
Google Play Newsstand
HP Print Service Plugin
Keeper
Mobile TV
MobilePrintSvc_CUPS
MobilePrintSvc_CUPS_Backend
My Magazine
myAT&T
Print Spooler
S Voice
Samsung Account
Samsung Apps
Samsung Galaxy
Samsung GALAXY Apps Widget
Samsung Link Platform
Samsung Print Service Plugin
Samsung Push Service
Travel wallpaper
Wallet (Isis)
ANT Radio
ANT+ Plugins
AT&T FamilyMap
AT&T Hot Spots
AT&T Locker
AT&T Messages
AT&T Mobile Locate
AT&T Navigator
Beats Music
BlurbCheckout
Business card recognition
Caller Name ID
ChatON
Device Help
DriveMode
Flipboard
Google Play Books
Google Play Games
Google Play Movies & TV
Google Play Music
Google Play Newsstand
HP Print Service Plugin
Keeper
Mobile TV
MobilePrintSvc_CUPS
MobilePrintSvc_CUPS_Backend
My Magazine
myAT&T
Print Spooler
S Voice
Samsung Account
Samsung Apps
Samsung Galaxy
Samsung GALAXY Apps Widget
Samsung Link Platform
Samsung Print Service Plugin
Samsung Push Service
Travel wallpaper
Wallet (Isis)