Came here to mention WindowGrid and WinNumpad Position.

WindowGrid: Drag window with left+right mouse buttons brings up a customizable grid. Release RMB to set first corner, and LMB to set opposite corner.

WinNumpad Position: Win key+Numpad key to snap window into corresponding position (eg- 7 for top left corner). Hit number multiple times to cycle through sizes. https://pbrs.weebly.com/win-numpad-positioner.html

Both are basically abandoned, but they work well along side the built in Aero Snap features.

Other old alternatives that have various levels of functionality (and clearly inspired many of the tools posted in this thread):

GridMove (free): Used to be my go to, but hdpi scaling and the Modern UI window elements borked it. Based on AutoHotKey, but surprisingly responsive, extremely customizable (though not very user friendly). Would love to see this make a comeback. http://www.dcmembers.com/jgpaiva/ https://github.com/jgpaiva/GridMove

MaxTo (paid): User friendly and pretty, but less useful since Aero Snap. Rarely updated, but alive. Nice if all you want is a slightly more control over the built in Aero Snap. https://maxto.net/

AquaSnap (paid): Very similar to MaxTo, but more refined. Free personal version is limited to single display functions. Updated rarely, but alive. https://www.nurgo-software.com/products/aquasnap

Windock (free): Crashes for me but works for some. https://www.ivanyu.ca/#/windock/

Freesnap (free): Not maintained, but used to be great. Haven't tried it in a while, but thought it deserved mentioning. https://mike-ward.net/freesnap/

Author of MaxTo here. It is very much alive, but there is just me working on it so progress is sometimes slow.

There are some very cool things coming in the next release: - support for different triggers, that lets you run specific commands in response to windows events. Basically our recipes feature extended quite a bit. - WinSplit-like hotkeys for those who liked those. Configurable. - lots of these small quality of life improvements

We are getting closer to a public preview of this, but shoot me an e-mail for a private preview.

That's a neat idea. So basically all windows must conform to grid lines. I wonder how well it resizes applications that don't want to resize.

It works almost too well. I've been using it for years and don't recall seeing a window it couldn't resize. I've seen it resize "unresizeable" windows in several programs that did not have scaling components, though. Consequently, you end up with the whole UI taking up a small part of the window.