Web Browser: Firefox

Email Client: Geary

Terminal: Gnome terminal

IDE: ???

File manager: Nautilus

Basic Text Editor: Gedit

IRC/Messaging Client: Empathy/Polari

PDF Reader: Evince

Office Suite: Libre Office

Calendar: Gnome calendar

Video Player: Totem

Music Player: Gnome music

Photo Viewer: Shotwell (definitely not Darktable or RawTherapee, far too complicated)

Screen recording: Built in Gnome screen recorder