We have YouTube and PeerTube playlists for these videos.

Plasma

• Ctrl + F9 + typing to show and filter open windows (YT_PLAYLIST_DUPLICATE | PT)
• Control your YouTube/Spotify/etc. from the media widget + middle click on volume widget to mute sound and media widget for pause&play (@aronkvh)
• Mousewheel scrolling on the sound to control volume, no clicking (YT | PT)
• Mousewheel scrolling on battery to control brightness, no clicking
• Mousewheel on the clock switches timezones if preconfigured
• Resize/Move your window by pressing a key — a littler after Plasma 5.20 is released (YT | PT)
• Alt/Meta + Middle Button — cycle through windows stacked one above the other
• Select and drag text from app to desktop to make a sticky note (YT | PT_MISSING)
• Long click on widget to bring up handles and toolbar (YT | PT)

Krunner

• =plot with KRunner & GNUPlot (Twitter: 82 retweets and 300 likes and Mastodon: 31 boosts and 30 likes) (YT | PT_MISSING)
• Simple math operations
• Unit / Currency conversions
• Switching between browser tabs
• Open applications ?
• Web shortcuts (gg: Google; gt: GitLab)
• Run commands with environment variables, e.g. LANG=C systemsettings5 to open applications in English for screenshots (implemented, but should wait until it lands on distros, added in 5.20)
• KRunner on center of screen like rofi ? (thanks to Alexander Lohnau)

Okular

• Print a page
• Select an image ?
• Annotation / Review tool (YT | PT)
• Presentation mode (useful with PDF presentations)

KDE Connect

• See incoming calls (and pause music/videos automatically when receiving/making one)
• Suspend computer with custom commands (YT | PT)
• Send files to a specified folder
• Ported to Windows (only post after the real release)
• Read & Answer SMS from the desktop

Kate

• Vi mode (is a KPart, so also in Kile, KWrite and KDevelop) It's already done and edited with kdenlive. Please let me know if I should add or modify something. (@sebelk) https://youtu.be/yDxSlSfIZy4
• Live preview of documents (e.g. markdown) (MISSING)
• Any app with KTextPart: Ctrl+Shift+Up/Down moves entire line/block selection upwards/downwards

Share/Purpose

• Share to Telegram
• Upload a screenshot to Imgur (YT_PLAYLIST_DUPLICATE | PT)

Dolphin

• Integrated terminal that follows your path (F4) and open terminal in folder (Shift+F4)
• Split view (F3)
• Create new tabs with familiar keyboard shortcuts (Ctrl+T)
• Git / SVN integration (needs plugin, TODO figure out for different distros)
• Nextcloud / Google Drive integration (similar to above)
• Previews for a ton of file types (e.g. Blender) (would be nice to know the amount of file types supported) (for extras: ffmpegthumbs, ffmpegthumbnailers, kdegraphics-thumbnailers)
• Multiple file rename (with numbers using # symbol)
• Open archives as folders
• FileStash/kio-stash: virtual folder/pane for bulk file management
• Filter bar (Ctrl+I) (YT | PT_MISSING)
• Privilege escalation (file operations requesting password) (D21795)
• Suggest New Name button when two files have the same name
• Duplicate here (check which version of Dolphin started supporting this)
• Tags (File Properties → Details → Tags)
• Easily share folders with SAMBA
• Google Drive support using kio-gdrive
• Show in groups (allows to simulate how the Windows Download folder looks like by separating content according to date, should probably check the easiest way to trigger, ask @ngraham ) ← What does this mean? (I have no idea too)
• Cool kio-slaves (timeline, man) and saving them to Places (see Miscellaneous: kio-slaves from KRunner)

KWin

• Meta + Arrows to snap windows (YT | PT_WAITING)
• Wobbly windows + 3D Cube (YT | PT)
• Animation for opening windows (Desktop effects → Window Open/Close Animation → Fade, Glide, Scale effects, try setting Scale to 1200 milliseconds and 0 for scale values)
• Switch animation for Alt+Tab
• Animation on mouse click
• Animation to show mouse pointer position
• Draw/scribble on your desktop using Meta+Shift ?
• Control where windows should be with window rules (wait for window rules kcm redesign to land on distros)
• Default touchpad gestures with libinput on Wayland (still at really, really early development, wait for full implementation)

Kdenlive

• Add audio wave form filter over video (see Audio Analysis)
• Simple motion tracking example
• Record audio directly from Kdenlive

Krita

• Tool for image referencing, should work well with image drag'n'drop
• Switch all keyboard shortcuts in-bulk to resemble Photoshop or Paint Tool Sai

Konsole

• Split and Sync input to terminal panes (YT | PT)
• Preview files holding Alt key
• Open listed files and folders just by clicking on them (YT | PT)
• Automatic activation of custom ssh profile (similar to putty)

Kontact

• Nexcloud calendar and contacts integration
• Archiving emails in zip/tar
• Gauge showing the possibility of an e-mail being spam with spamassassin

Accessibility

• Meta+Minus or Meta+Plus to zoom in and out on the screen (this is so useful!)
• Track Mouse desktop effect for visually impaired

Miscellaneous

• Run application using dedicated GPU (see userbase.kde.org)
• Respond to Telegram message directly via notifications
• Browse icon in cuttlefish to find the perfect icon
• Kioslaves (man:/, zip:/, etc.), also available from KRunner (See Dolphin's cool kio-slaves)
• Spectacle: new annotation support
• Drag a screenshot directly from notifications/Spectacle to the application you want (doesn't work with containers like flatpak iirc)
• Drag a picture from the web browser to the desktop to set the background (YT | PT)
• Yakuake show-off
• Ctrl+Shift+T to open a new Konsole/Yakuake tab
• KColorChooser and the color chooser widget
• Scan WiFi QR code from plasma-nm with phone
• Add sounds to your notifications and login (bugged, presumably 422948)
• Change which widgets are shown in the tray

Notes

• YT_PLAYLIST_DUPLICATE — duplicated in YouTube playlist
• PT_MISSING — missing on PeerTube
• PT_WAITING — PeerTube inaccessible for now
• MISSING — done but absent on every platform