Identifying Uncraftables

Solution 1:

This doesn't filter out uncraftables (I don't know of a way to do that), but it may be helpful for your goal of disposing of golden cards:

If you search for the keyword “extra”, then the collection viewer will show every card you have extra copies of (>2 for non-legendary and >1 for legendary), counting regular and golden cards together. This is not the same as Mass Disenchant, which counts them separately.

Therefore, all the golden cards you see with this filter are ones that you can disenchant without losing any useful deck-building capabilities. (Don't double click and disenchant 2 goldens if you have only 1 regular!)

(I don't know what the “extra” filter would do with an uncraftable card that you can gain more than 2 copies of, but as far as I know there are no such cards.)