You could write your own with AutoHotkey:
#=:: ; [Win]+[=] WinGet, window, ID, A InputBox, width, Resize, Width:,, 140, 130 InputBox, height, Resize, Height:,, 140, 130 WinMove, ahk_id %window%,, ,, width, height return
Demonstration:
Before: 640 x 480
Press Win+=.
Enter a width:
Enter a height:
After: 400 x 300
Note: To set a length to
0
, you have to input0
. An empty value is ignored. For example, if you only want to resize the height, leave the width blank and enter a value for the height.
For the curious: 0 x 0
As you can see, a window with a title bar and controls has an absolute minimum size.