Web Browser: Chromium

Email Client: Gmail (web), Protonmail (web)

Terminal: gnome-terminal

IDE: Sublime Text 3 (non-free), Visual Studio Code

File manager: default

Basic Text Editor: nano

IRC/Messaging Client: HexChat

PDF Reader: default

Office Suite: LibreOffice

Calendar: none

Video Player: mpv

Music Player: unsure, i would go with DeaDBeeF and Spotify (non-free)

Photo Viewer: ???

Screen recording: none

Extra: KeePass, git, gpg