In the VSE is there a way to snap strips to the begining of your editing? For example you've deleted the first strip of you editing, your editing now starts at frame 200 and you want to move all of your strips to frame 0 or frame 1, is there a simple way to do that snapping to the begining of the VSE?
Group all of your strips (Make them a Meta Strip Ctrl+G) and then with your current Frame being 1 (position the green playhead) press Shift+S to Snap the Meta s to the beginning. Alternatively set the Meta Strips Start Frame to 1. Then UnMeta/ungroup the Strip again: Alt+G.
I would select all clips and press G-200 (if your edit starts at frame 200). This will move all clips 200 frames to the beginning of the timeline.
If you have Sync Markers enabled (View > Sync Markers), the selected markers will move with the clips.
To select all markers press A with your mouse over the timeline.
The Extra Sequencer Action Add-on has a Ripple Delete feature. With that you can just create a Dummy Strip (like a Color Effect Strip) from Frame 1 to the Frame before the rest of your footage that you want to move. And then perform this Ripple Delete on that Dummy Strip which should move the rest of your strips afterwards to the left including the Keyframes, etc...