I previously kept Grab.app on Mojave 10.14 by simply copying it over from High Sierra 10.13. I prefer the simplicity of Grab over the new Screenshot.app, and I hate that Screenshot adds a drop shadow.
Alas... Grab from High Sierra 10.13 is dead on Catalina 10.15, as Apple did not maintain backward compatibility in AppKit. RIP.
dyld: Symbol not found: _OBJC_CLASS_$_NSCompressionGroupTouchBarItem Referenced from: /Applications/OldGrab.app/Contents/MacOS/./Grab Expected in: /System/Library/Frameworks/AppKit./framewoprk/Versions/C/AppKit in /Applications/OldGrab.app/Contents/MacOS/./Grab
For screen shots “my way”, see my Touch Bar Quick Action (Automator script), which uses the
screencapture command line. You can even use Automator to create your own .app that leverages the command line!