Nuclear triad
Israel is known to have nuclear-capable aircraft and land-base missiles, with the addition of nuclear-armed submarines this would mean that they now have a full triad of land-, air-, and sea-based nuclear delivery systems some of which would be invulnerable to a first strike by an enemy for the first time in their country's history. No other nation in the Middle East in known to be in possession of nuclear weapons, even though Iran, Iraq, Syria and Libya have started development programs that were never completed.
Military history of the Soviet Union
Most of the nuclear stockpile was inherited by Russia. Additional weapons were acquired by Ukraine, Belarus and Kazakhstan. Amid fears of nuclear proliferation, these were all certified as transferred to Russia by 1996. Uzbekistan is another former Soviet republic where nuclear weapons may once have been stationed, but they are now signers of the Nuclear non-proliferation treaty.