Customization on Windows is good with themes and all, but I was curious to see what programs people use to add to the Windows shell, instead of replacing or theming it.
I use Smart Taskbar, Windows Caffeinated and Windows Toolkit that all add icons to the system tray, in the same style, that do the following:
— Smart Taskbar: Clicking the icon will hide the taskbar automatically, and can be set to show the taskbar when an app is windowed, but hide when maximized.
— Windows Caffeinated: Keeps your PC from sleeping. You can use PowerAwake with MSPowerToys, but I don't like the icon.
— Desktop Toolkit: A Swiss army knife of utilities. It's hard to describe but, it has pinned apps, custom folder pins, timers, screen recording, color picker, recent files, etc. I like to pin custom PowerShell scripts here.
— Toggle Desktop Icons: This app lets you double-click the desktop to hide icons, and adds a system tray icon. It's similar to HiddenMe on macOS.
I hope this leads to a great discussion and sharing of information!
winaero tweaker is a great all round "hidden options" tool
7+ taskbar tweaker allows scroll on taskbar for volume, which once you're used to is hard to lose
~~i'll edit with more in a short while~~
monitor profile switcher - absolutely invaluable if you use multiple monitor layouts
iconviewer - somewhat niche, but an easy way of seeing all icons in multiple dll files
pangobright - washes out the desktop so it's not a real replacement for brightness, but if you have a migraine or something and want your screen darker at any cost this is handy
pasteintofile - does what it says on the tin; very handy
rbtray - minimise any window to systray (i'm not linking this one as i only have the exe file, and i can't remember which of the multiple versions available it is)
retrobar - i don't actually use this as it doesn't work with 7+tt, but it's a neat idea
universal pause button - pause any game (or programme, i guess) from the systray
touchcursor - doesn't quite fit the question, but it's so good i'm including it. basically dreymar's colemak extend layer, but without the need for ahk
open-shell (was classic shell (was classic start)) - better start menu with a multitude of options, and some taskbar improvements
cairoshell - never properly used it, and it doesn't quite answer the op question; but i want to draw attention to the almost complete shell replacement for windows
powertoys - others have mentioned it, but i'm adding it here so it's a more comprehensive list
wox - simple, fast launcher that integrates with everything
windows store apps:
twinkletray - ddcutil monitor brightness tray app (non-uwp equivalent: clickmonitorddc)
ear trumpet obviously - better volume slider(s)
modern flyouts - better volume adjustment popup