What is your favourite less well known app/software?

For Windows users, I want to recommend PowerToys: https://learn.microsoft.com/en-us/windows/powertoys/
The "toys" that I use a lot are: PowerToys Awake: to keep my laptop awake even if I'm away from keyboard for a while.
Fancy Zones: to create my own layout of windows, especially on the ultra-wide monitor I have at work, it's easy to have 3 smaller windows next to each other according to my layout.
Mouse Utilities, I often can't find my mouse cursor, just pressing a hotkey will literally spotlight the cursor.
Quick Accent, especially for multi-lingual people this is really handy, though it takes a bit to get used to its working.
- I use fancy zones, and also the one that finds your mouse cursor as I'm always losing it, and the always on top mode for when I don't want a teams call to vanish while I do something else
  
  Be like me, just make your mouse cursor neon green and huge.
- FancyZones is literally the only thing I'm missing from Windows after switching to Linux. I've looked around stack and reddit but have only found posts asking for that functionality, haven't found a solution. Is there a DE/window manager/etc that has similar functionality?
  
  Isn't Fancy Zones just window tiling? KDE has a tiling built in (hit meta+t to set up and then hold shift while dragging a window) and there are a hundred way more nerdy tiling window managers.

LocalSend is open-source and great for file transfer (or even just sending text) between my devices.
- Never occurred to me to even look for such a thing!

Greenshot is free, open-source, and the built-in image editor is perfect (for my use-case, ymmv). ShareX is also FOSS but more well-known.
- Another vote for Greenshot, I use it nearly daily for my work.
- The last version on the website is from 2017. I wonder what's going on? The repo seems to be alive. I used it for years but switched recently to ShareX since Greenshot GUI can't really handle high screen resolution
  Edit: Just checked the Blog. They didn't had time in the last years but it seems to pick up speed again now. A new version is coming.
  
  Yeah, it's been solid/stable but no new developments until 1.3 is coming. You can download the pre-release version if you want to try it again, because that version has zoom options. I imagine that's what you missed, unless you meant something else with older versions not handling high res well
- Screen2Gif is super useful when trying to show someone how to do something without doing a zoom or screen share. And gifs post in slack really well.
  
  ffmpeg -video_size 1920x1280 -framerate 25 -f x11grab -i :0.0 output.gif
- I used to use Greenshot but switched over to Flameshot. Also Free software, but has better and easier editing tools. The numbered arrows are so handy.

Bulk Rename Utility for Windows:
https://www.bulkrenameutility.co.uk/
- Here's a bunch of equivalent things for desktop OSes.
  https://en.wikipedia.org/wiki/Batch_renaming#List_of_software
- dired
  
  This is so powerful, I use it all the time.
- PowerToys has something like this roo

Candle.
It's an android app that uses your display to make a "glow" to light a room rather than using the camera flash like a torch.
It's in F-Droid.
Obviously the camera flash is more powerful if you're outside or whatever, but using the display this way is way better inside. That tiny little dazzling pin-prick of light is just... unpleasant.
With candle you can also set whatever color you like. Red is nice to avoid waking people or ruining night vision.
I discovered this app when we had twins and waking up to nurse them overnight. Gonna sound weird if you've not been through this but basically they won't really wake up they make a gentle sooky noise, and you put a bottle or boob in their mouth and they suckle while they sleep. If you turn a light on they're gonna wake up which is sub-optimal.
- This is the first app in this thread that made me go "I need this!" and immediately downloaded it!
  Thanks!
  
  It's weird how much i like this app.
  It's free / open, solves a problem elegantly, and I use it all the time.
- One of the first type programs I got when i got an original iPad touch. Loved it!
- I fell down the everyday carry flashlight pipeline / rabbit hole instead. Not recommended if you don't want to ruin your perception of what's a great tint of light to you.

I'm surprised how many people don't know about a Linux utility called "fuck". When you make a mistake on the command line and get an error, you just type "fuck" and it looks at what happened and suggests a fix. If this looks correct - and it almost always is - you just hit Enter and it types that in for you. Best thing ever!

If any of you still aren't using YT Revanced... why?! So yeah, that one, cause God knows my limit for insipid and repetitive ads is extremely small.
- pipe pipe
  I've been using this for 6 months or so and it seems a lot more stable than previous iterations.
  Also freetube for linux desktop
  Finally pinchflat for archiving content because IDK how long these apps are going to keep working.
  
  Oooh, thanks for the recs!
  
  I love pipe pipe, especially the live comments view that emulates nico nico douga style. It's annoying for most since the comments obscure the video going past it, but it's a bit of a nerdy fun to me.
  
  I'd like to add grayjay
- Because I don't watch videos on my phone.
  YouTube has broken uBlock and Firefox. Still works on Edge, but I'd rather not switch browsers back and forth. Yes, I've cleared my cache.
  Anyone?
  
  Is it because of your religion or...?

Qalculate is a fancy calculator available for Linux, MacOS and Windows. I use it for calculations that involve unit conversions, but it can do much more.
- I acutally use Qalculate as well when I have to use my Windows laptop
  Fuck Microsoft for not bothering to improve on the calculator app for decades.
  
  They have improved. You can do unit conversions, great binary/hex/oct calculation/visualization, do graphing, calculate dates. It honestly is very good.
  
  Best of all, you can also install it using winget. Yes, package management through the cmd in Windows. Well, as long as you’re the admin of that computer. Don’t expect this to work with all corporate laptops.
- And Android!!
  
  Oh that’s a good point. Totally missed that one. Seems that there’s also a webapp for other platforms.

Just in case, a big thread this week for Linux users: https://feddit.org/post/14167855

Everything, the only thing that makes Windows usable.

URLCheck on Android. Displays a popup on opening links allowing editing the URL before opening (with such features as removing chosen parameters with one button), applying transformations like Shitter→Nitter, http→https, sharing the URL, copying and selecting the application to open the URL in. Oh, and if you decide to open in Firefox or Fennec, you have the option to open in the incognito mode. Can't imagine using Android without it now. Absolute gamechanger
- From the store, or else where???
  
  F-Droid. IzzyOnDroid has a tad quicker releases

https://logseq.com/ a personal knowledge base with markdown and has a whiteboard feature. I live in this program now. From daily little notes and reminders to full on script writing. It's a little clunky but it works with my brain. Other similar programs are notion, obsidian and anytype.
- I can second logseq but it has a bit of a steep learning curve. Not impossible but you have to learn how logseq wants you to use their software and then it becomes powerful.
  
  What's your take on how they want you to use their software? I throw down bullet points in the journal, tag them with big overarching themes, and link to old journal entries sometimes. Am I missing something important?

Windirstat
A windows app that shows you the space things are taking up on your computer so you can easily delete them. Usually helps me clear out a ton of space.
- I prefer WizTree. It'll show you space usage, but you can also search for files, and it's incredibly fast.
  
  It's also much faster
- Wiztree and Treesize are both much faster.
  Windirstat is still relevant... But slow.
- dua-cli is good for this.
- ncdu in Linux

OmniDiskSweeper. Forget apps that help manage disk space with some ugly graph that's difficult to understand. This just lists files and directories with the heaviest / most space used from top to bottom in a file tree. Essential. Here's what it looks like:

Converter Now: An all-in-one convert everything to everything app.
Light Meter: Calculate light levels and color temps for photography and videography.
Stellarium: Honestly don't know how "well known" it might be. But it's fun to point at stars and planets.
- +1 for converter now, close to my most used app on Android.
  
  It's on F-Droid

BeeCount - A app to keep track of patterns while crafting. I like that I can have an overall row count, but make separate counters nested underneath for the same pattern (ex: You're on row x, but row a for a cable repeat).
Olauncher : A simple launcher for android. Less busy.

https://www.sportismygame.app/ Helped me get of my fat ass and move every once in a while

Kiss Launcher
The smallest quickest launcher for Android
Start programs from your new home screen by typing in a few letters.
The app adapts to how you use it, making finding what you want even faster.
- Flashbang warning for anyone following that link.

SimpleX has file sharing too now, it's great :)
Sadly limited to 1gb afaik
- Use PeaZip (which is better than 7-ZIP because it's cross-platform) to split large files into as many smaller chunks as you'd like.
  
  I never realized 7zip was Windows only :-(
  Thanks for sharing
  but yea, anyways, native support for bigger files would be better. Not easy to split files on mobile

https://freefilesync.org/
- In a similar vein, rclone
- This thing is a lifesaver

DevToys. It's an awesome cross-platform swiss army knife for developers. It's got most of the little tools that you would look up online.
Formatters, encoding/decoding, validators etc.
I really love it!

File converter in the context menu. Handles a lot of common formats, batch converting, nondestructive, and the presets are all customizable. https://file-converter.io/
Ear Trumpet - Replace window audio button with one that gives you per app, and device control. https://github.com/File-New-Project/EarTrumpet

Double Commander
- And for Linux: Krusader
  https://krusader.org/

ncdu, it's a pretty decent utility for interactively exploring your rectum whilst traversing the deep hierarchical layers of your soul

sl is a classic command line program for something harmlessly pointless
calibre for digital library software (cataloging books/docs/articles)
Comic book reader, it's a cbz/CBR comic book archive reader that tries to do the panel/smart auto zoom that used to be a part of comixology until Amazon bought it to kill it as competition to their shitty books app
- I donated to calibre, makes my eBook viable.

Freedom - https://freedom.to/
A very powerful cross platform website/app blocker with a lifetime membership option. Works well for blocking multiple fediverse domains.

Pixelorama, a good, open-source pixel art program

Apparently many don't know libre office is thing and free. Seeing people ask for goggle doc alternative amd all they need is a word processor.

ClickBook - dunno if it's even available anymore, but like 20 years ago it was either a standalone or add-on that formatted Word docs for printing. I think it cost $35. You could lay out say a tri-fold brochure or a folded-in-half and stapled booklet and it would rotate, combine and print the pages in the correct order. My wife and I used it endlessly to produce publications for our kids' school. If your printer could only print on one side, there was a quick setup procedure that would would figure out how you should rotate or flip the stack of pages to do the second side. I haven't used Word in years so for all I know it might have these capabilities natively now, but in its time ClickBook was probably the most worth-it program I ever bought.
- Can you alter the header only on page 6? Or rotate pages 3 and 5? Because that's the kind of wizardry that Microsoft refuses to implement in Word.
  
  I never tried to rotate individual pages or do special headers, but I don't know - it had many features I didn't use.

Small apps available on Flathub that have only one purpose
Latest examples:
Trilium Notes: note-taking
Foliate: .epub reader
Shortwave: radio player
My brain works in a way that 1 software = 1 single and unique thing, and you shouldn't have to go through a roundabout way to do that thing.

DGT GTD is an old Android app for task tracking. It is ugly and incredibly useful. Lives entirely in the phone, no cloud subscription, no paid plans, nothing.
I have used it forever. There is no good alternative.
The current app "Chaos Control" is a close contender, but pricey and cloud connected.
https://play.google.com/store/apps/details?id=com.dg.gtd.android.lite

QuickLook for Windows. Coming from a Mac this thing is super useful to replicate that functionality on Windows.