ResizeEnable lets you resize non resizable or unresizable windows and dialog boxes with fixed sizes. Download freeware for Windows 11/10.

AltDrag lets you move, drag, resize and manage several separate windows at the same time and move parts of them off the screen easily in Windows.

Windows: reSizer is a tiny utility that moves, resizes, repositions, and tweaks the appearance of open applications and windows with keyboard commands and hotkeys.