Sorry if there are duplicates, but here's what I've had Greenified and not had any conflicts (yet):
Calculator
Dropbox
Exchange Services
Face Unlock
Google Play Store
Google Search (don't have the widget installed)
Maps
Multimedia UI Service Layer
Samsung DM Service
Samsung keyboard (I use SwiftKey)
Samsung text-to-speech engine
SensorService (got rid of S-Health but wanted to keep it in case there are any other apps in the future that use it)
Settings
System Update (KNOX is tripped, no point in having anything OTA-related)
TouchWiz home (using Apex)
YouTube
I've also frozen:
HTML Viewer,
VPN Client
VpnDialogues
Everything else I just flat-out removed completely including all Samsung apps (Galaxy S4)
Things listed in this thread that I HAVE kept:
Animated Photo/Best Face/Drama/Eraser/
ANT HAL Service (and anything related)
Assistant menu
Clock (alarms)
Live Wallpaper Picker (discovered Parallax wallpapers using less than 10mb of memory
)
MusicFX (it's either this or Adapt Sound that is needed to be able to select Viper FX)
Ones I'm not sure about:
Bluetooth Share
BluetoothTest
com.sec.app.MIPErrorNotifier (I was unsure about this one, but haven't had any obvious problems in a few days...
)
com.sec.android.app.FlashBar (testing per above post)
Market Feedback Agent (testing per above post)
Contacts (Contacts+ hooks into it, needs testing)
TestService
--------------------------------------
EDIT:
Bluetooth Share does not like to stay Greenified
com.sec.android.app.FlashBar does not like to stay Greenified
Market Feedback Agent is confirmed safe