just have a simple issue of finding out how to jump to front or back key-frames, as I am currently typing in the number each time, but hope there is a simple short-cut / hotkey. Inside grease pencil in particular, if different to 3d etc. Thanks.
In Blender2.79 ,Grease pencil keyframes are shown in the Dopesheet ->Grease pencil Panel. Hotkeys should be same for other Blender versions as well.
IMPORTANT - Mouse Cursor should be in the Dopesheet Editor for Blender to recognise the scope of the Hotkey.
For moving inbetween keyframes, following Hotkeys are available
1.First/Last Timeline Frame - Shift Ctrl UpArrow /Shift Ctrl DownArrow
2.Next Keyframe - UpArrow
3.Previous Keyframe - DownArrow
4.Play/Stop Animation - Alt A/Shift Alt A (Version Blender2.79 and below) &
Play/Stop Animation - Spacebar (Version Blender2.8 and above)