I would like to list the available labels matching a particular string applied in the view.
Hmm. I'm not entirely sure about this although the following will list all labels used for a given VOB (entered using ClearTool command line application).
lstype -kind lbtype -invob vob_path_and_name -short
for example with a View mapped to drive U: VOB "Some_VOB" would be:
lstype -kind lbtype -invob U:\Some_VOB -short