When Windows 95 launched nearly a quarter of a century ago, it brought a whole new way of interacting with the windowing environment on users’ PCs. The Start menu was introduced (and the grand launch event had the execs “dancing” to ‘Start Me Up’ by the Rolling Stones – chosen because of its “Start” association, presumably, rather than the lyric “you make a grown man cry”), and after a short-term diversion in Windows 8, the Start menu reappeared in Windows 10, and is still evolving.
After the Win95 initial release, the development team behind the Windows Shell came out with a bunch of useful utilities; things that at one point might have shipped as Resource Kit tools, but were aimed at a slightly broader user base – and so the Power Toys family was born.
There were often capabilities in the OS which could be enabled or disabled by the flick of a setting in the Registry (also new in Windows 95, in an attempt to put all the settings stuff in one place rather than having INI files everywhere). Telling an end user to go an start Registry twiddling is a potential recipe for disaster, so the Power Toys included utilities like TweakUI, which exposed some of the settings.
Various other Microsoft products embraced the idea of Power Toys, but the whole thing was killed off in the wake of the intensive code reviews required as part of the Trustworthy Computing (TwC) initiative in 2002. See more of the history here (though the page is 15 years old so pretty much all the links are dead).
In late 2019, it was announced that PowerToys was coming back – this time, as an open source project supported by the dev team but ultimately driven by a wider community. The goals for v1.0 have been published and recently the 0.15 release was made – get the latest version here.
So far, possibly the most useful app in the current build is FancyZones, which allows you to have more control over window layouts than simply snapping to the left or right – handy if you have a massive monitor or two, and want to tile multiple windows side by side.