After having created the insufficient-storageinsufficient-memory including tag excerpt and wiki, now used by 10 questions, during re-tagging I discovered the storage-full on the last question, which is used by 9 questions currently.
Both tags are not really equivalent (insufficient-storagememory directly refers to the "insufficient storagememory..." error, thus dealing exclusively with the devices' internal storage -- while storage-full is much broader (at least from its name, though ~80% of the questions tagged such seem to explicitly refer to "insufficient storage"memory", and the remaining 20% at least implicitly).
My idea was to merge the two, and convert storage-full into a synonym for now. So if we really feel we need a separate tag by that name at a later point, it would be easy to retain. At the moment I do not see much sense in a separate broad "storage-full" tag (my, if the card is full one needs to delete something, right? Or buy a larger card).
Please keep insufficient-storagememory as the main tag / merge target, as it already includes a tag wiki with "first aid" as well as a wiki excerpt :)