Because my last one was pretty popular (and is deleted now that I've set my posts to expire after 3 months), here is another list of my favourite #FOSS #software :

#Cryptomator -- encrypts files saved in a sync folder before they get uploaded to the cloud; great if you use Google Drive, Dropbox or another provider that doesn't offer end-to-end encryption (or, even if you do - belt and braces)
#Syncthing -- peer-to-peer file syncing over your local wifi network
#ShareX -- similar to Syncthing, but does not have to use the internet. Use your phone's hotspot to connect with a peer and share files via a web browser interface. Lighter and simpler to set up than Syncthing.
#Picocrypt -- on-the-fly file encryption
#LibreOffice -- free office suite, an almost drop-in replacement for MS Office
#KeePassXC and #KeePassDX -- XC is for desktop and DX is for Android only; offline password manager, saves your credentials in a file to your device that you can decide to back up (or not) manually; compatible with Yubikeys, OnlyKeys and other #FIDO2 devices
#LessPass -- stateless password generator that uses what you input every time to generate the same random-looking password every time
#Diceware Passwords -- Android app that uses data from random.org (or Android's built-in pseudorandom number generator) to create passphrases
#RemoteKeyboard -- link with #PuTTY to type on your Android phone from your laptop over wifi
#GnomeBoxes -- run virtual machines, like VirtualBox

Some of my favourite #FOSS software:
- #LibreOffice
- #Syncthing - sync files between two or more devices over LAN
- #Tusky - Fediverse client for Android
- #Picocrypt - on-the-fly file encryption
- #Cryptomator - encrypt your files before uploading to the cloud
- #Nextcloud - self-hosted cloud server software
- #Joplin - Markdown-formatted notetaking synched (optionally encrypted) to a cloud server
- #KeePassXC and #KeeWeb - Password vault, entirely offline
- #LibreWolf & #UngoogledChromium