I can't live without fre:ac. It's an open source project aimed at being the best and most accurate CD ripping and audio converting software. It supports Linux, Windows, and I think Mac OS as well. It's very similar to Exact Audio Copy for Windows. I'm a big music fan who still rejects streaming so I need this.
Joplin because I struggled for years with a consistent way to keep and refer to notes that I could find easily at a moment's notice and access from any device, anywhere.
(Please don't tell me about how you use a text editor and markdown in your home directory Like GH* INTENDED because I tried that FOR A DECADE and it didn't work for me. I'm old and cranky. Get off my lawn! :)
Being able to quickly change audio outputs is awesome, I am always bouncing between headset and speakers. Also the pop up volume mixer is better than the built in one. Been using ET for years and years, can pry it from my cold dead hands.
When obligated to pick one it'd be AutoKey: “a desktop automation utility for Linux and X11.” Relatively and subjectively speaking, without it I feel hampered like crazy while most other software is “just” convenient.
Since the Internet in general is getting harder to find genuine information, it is becoming increasingly important to save anything important to you. One day it could just disappear without warning. Obsidian can be used for an offline knowledge base. Design it however you like. I do recommend NOT watching YouTube Obsidian “gurus”, their system works for them not you.
My first thought is that my work requires office365 mail and my discovery that davmail exists has been a godsend. I'm not going to install outlook on my linux pc, so being able to check those emails using any client (claws in my case) is a massive convenience upgrade from relying on firefox to login.
Windows: PowerToys. First thing I get approval to install on a work machine. PowerToys Run (Launchy on roids) saves me from the built in Windows search, a quick calculator, etc. PowerRename gets used more frequently than I care to admit. Video Conference mute is a second nature key combination. Can't remember the name of the window manager module but it is a key part of my workflow.
Android: As I've mentioned in a reply, Edge Gestures has been on my phone for years (first installed on a Pixel 3). Having 10+ apps accessible (especially 2FA, password vault, home assistant) from any screen, plus gestures for quick controls (flashlight, brightness slider) is incredibly handy. And unlike the notification shade, the edges of the phone can actually be reached with your thumb.
Linux: Docker. It's been an instrumental part of building out my home server which allowed me to kill my Microsoft 365 & Google One subscriptions. For me it has been the gateway drug in to learning more and more about self hosting - to Proxmox, LXCs & VMs, pihole and unbound, etc.
On Android, it's probably a little utility software called Quick Cursor (it's not FOSS).
It's incredibly convenient being able to spawn a cursor on your phone from thin air that you can use to reach the "unreachable" portions of your screen, especially if you are holding your phone with one hand. Besides being a "phone touchpad" it has a bunch of ways of triggering actions/shortcuts, for example: volume or brightness control, launching an app (I use it for launching a floating calculator, notes...), opening notification shade, copying text (it can copy any text that is under the cursor, even if it's not selectable)...
It's not that I couldn't go without it, but it changed the way I use my phone and it would feel really weird without it. It feels like it should be a part of the OS.
Android. As bad as it is, if I had to use iOS or Linux phones it would be even worse, at least with the current state of Linux phones.
But actually, maybe if Android didn't exist, the FOSS community would focus more on Linux phones and they would be an actually good option. Maybe Android shouldn't exist?
LiGNUx, VLC, Firefox w/Ublock, KDE Connect, Dolphin, Kate, KDE. Vim, i3wm, Keepasses, yt-dlp, deluge, freecad, librecad, slic3r/cura. Some of these are clearly redundant or overlap. My use cases vary
Non-foss: Steam library.
I wouldn't spend so much time on the PC if I had to pay a premium for every little thing much like I've experienced with my arts-related hobbies.
Lightroom Classic (I've tried Darktable, just not for me. I take a lot of photos on my DSLR and I've been using Lightroom since 2015 so for me it's worth eating the awful monthly subscription that I split with someone else.)
Anki (flashcard app, very popular among med school students and folks trying to learn new languages. Open source and tons of useful decks available. I've aced plenty of exams thanks to Anki.)
Bitwarden (finally caved and got a password manager-- could not be happier)
CHIRP (the best for programming handheld, mobile and base station radios)
CrystalDiskInfo (great for checking the health of SSDs and HDDs)
DaVinci Resolve (love using this for video editing-- pirated copy was easy to find)
Deluge (great for torrenting)
foobar2000 (I love it for music)
Greenshot (useful screencapture software)
inSSIDer (great for wifi analysis)
IrfanView (very good for photo management)
MusicBrainz Picard (amaaaaaaaaazing god tier music management software to get all the correct metadata/album art)
reWASD ($7 but it's so good for no BS macro'ing of keyboard/mouse/gamepad shortcuts and profiles. I have two PCs and two mice + gamepad attached to my PC and this software is very helpful. I think the license is for life.)
WizTree (SSD/HDD visualization tool that is useful for figuring out what's taking up too much space on your drive)
I've got some videos on my phone I might want to watch on random computers, so I serve them up with NGINX. I've got wget-created mirrors of some old websites on my phone, so I serve them up with NGINX. Other files I may want to move out from my phone to untrusted computers on the network can too be served up simply by NGINX.
I've got the full Wikipedia zim file from Kiwix on my Micro SD card, so I run kiwix-serve (behind NGINX).
I've got all the music on my phone, naturally the phone is then running my Navidrome server (behind NGINX).
Of course, I may want to manage this from a computer, so it's running SSH server.
My phone is always connected to VPN and uses NextDNS, naturally I may want to use this with other computers, but I can't install software to computers I don't own (I mean, I can, but ... it would be disliked), naturally it is then running Tiniproxy HTTP proxy server.
Some desktop GUI apps can be useful on a phone too. noaa-apt, Kid3, Audacity, desktop Firefox, Handbrake because I am too dumb for ffmpeg, so I run XFCE DE on it. Naturally, I can access it from a computer (I know) too, after all it's accessed via a VNC server.
Am I stupid enough to expose something using HTTP protocol running on my phone to the internet? Of course I am! I can use cloudflared.
Do I want to encrypt a file? I can use GPG.
Do I want to create a compressed archive? I've got TAr and GZip.
Do I want to browse Gopher? I've got Lynx.
SSH or telnet somewhere? The clients are there.
Does everything from GSuite that I need it to, but without looking through everything I upload, and analyzing it for advertising and other purposes that I wouldn't consent to.
Shove-it, an ancient Windows utility by Phord Software that shoves any half-offscreen windows back onto the monitor so that you can get to all the gadgets. Phenomenally useful. First thing I install on any new build.
KDE. Been using it since v3, tried various other systems like Gnome, Enlightenment, XFCE etc. and I've always been coming back to it. KDE just feels very intuitive and easy to use.
I've gotten very used to this little free app called Audio Switcher that makes it way easier to switch back and forth between speakers and my headphones.
On foss category KDE connect. I use my phone as keyboard and mouse to navigate my laptop/PC while sleeping on my beanbag. You could use wireless mouse or keyboard but i find KDE more convenient. Also i can control the media from there
For non foss believe it or not it was google lenses, i used to use Accessibility Button setting floating bubble just for lense easy access from google assistant. They removed it and change it to "Gemini AI" now you need to screenshot and open the separate app.
Before that you just open it from accessibility and just search the screen. Translate, searching products from your screen, copy paste text from image you can do it from there no need for screenshot.
Edit : Just found out that you can change the default assistant function from the assistant app. I can use the lens with accessibility setting again *Horay
PaintTool SAI 1 is my beloved, I don't care how old it is, I love it and it's just so comfy to me!
For those who may be wondering, PaintTool SAI is a lightweight drawing program developed by Systemax Software that was released in 2008. The "SAI" part of its name is unrelated to AI, and is an acronym for Systemax Advanced Illustrator. It was developed by one person, Koji Komatsu, and he runs Systemax all by himself. What a guy!
JPEGView It's a simple but powerful image viewer (don't be misled by the name, it can view most any standard image formats).
It feels weird to even have an opinion on such a simple piece of software, but this is the type of tool that reminds you of what software could be like. When you open an image, you see the image. No loading time. No unnecessary toolbars. No fucking pop-ups to update the software to get the latest AI tools.
Don't get me wrong, it's plenty powerful. It's got all the tools you'd expect: viewing EXIF data, cropping, rotating, brightness/color correction. It even has some more advanced tools: navigating collections of photos (including nested folders), viewing a collection as a slideshow or movie, perspective correction, batch-renaming... The impressive part is that it does all this without getting in the way of it's job: viewing images.
Unfortunately, the project has been abandoned, though it appears to have been forked here (I haven't actually used this version, but hopefully they haven't changed too much).
Neutron Music Player for Android. Yes the UI is outdated, but the efficiency and feature set cannot be beat. It's so efficient on battery life compared to both streaming music services like Spotify, or any other local music player Android app. And the feature set is incredible. The full parametric equalizer, built in frequency response correction for almost any headphone model you can name, volume normalisation, EQ presets, direct USB access to USB DACs to bypass Android volume or format limitations, crossfeed for headphones, and that's just what I can think of now. I'm sure there are more features I haven't even used yet.