Three cursor-based selection commands for the VSE, with careful handling of locked strips, plus two commands for selection of locked or mute strips.
—Add Select All Strips Left—
Selects all strips with end frames up to the cursor position, except for unselected locked strips. Anything selected before the command is run will remain selected.
Keyboard shortcut: Ctrl-[
—Add Select All Strips Right—
Works the same as the Left command, but on all strips with start frames from the cursor position.
Keyboard shortcut: Ctrl-]
—Add Select Current Strips—
This works two ways. If the cursor is within a strip, but not on the start or end frame, the strip will be selected. If the cursor is at the end or start of the strip, the end or start handle will be selected. If the cursor is placed on a cut between two strips, the end handle of the left strip and the start handle of the right strip will be selected. This works across channels. The feature is most useful when the timing of a cut between strips needs to be adjusted.
Keyboard shortcut: Ctrl-.
—Select All Locked Strips—
If locked strips exist in the sequencer, this command will deselect everything presently selected and select the locked strips. A notice in the Info bar will state the number of selections. If there are no locked strips, present selection will remain and an Info notice will likewise appear.
Keyboard shortcut: Shift-Ctrl-K
—Select All Mute Strips—
Same as the Locked version above, but for mute strips.
Keyboard shortcut: Shift-Ctrl-M
More details here: http://blendervisionpro.blogspot.com/2015/02/bvp-sequencer-selection-addon.html
The addon can be downloaded directly from Google Drive:
https://drive.google.com/file/d/0B4U5LpqB83HWYWFXWElXTnZDdUE/view?usp=sharing
…or you can copy and paste it from the page linked to above.
I rely on this addon a lot now, and I hope it is useful to others.