As a Windows user, I always wanted a tool that provides the ability for me to drag to scroll. Adobe Acrobat has this feature inbuilt. I want something like that for every windows application. There used to be a utility application with name MouseImp 12-15 years back, but was abandoned and no more work with Windows 10 unfortunately. I believe Mac has Smart Scroll, which provides such functionality.

Any missing application or feature which you always wanted?