There's still Kaliningrad.
Now completely surrounded, on land and sea, by NATO members.
An interesting alternate history scenario is if Kaliningrad was given to Lithuania, like Crimea was given to Ukraine in the early Kruschev period. Now that I think about it, another interesting scenario would have been if the Ukrainian SSR leadership refused the transfer of Crimea to their control because of similar reasons why the Lithuanian SSR refused adding Kaliningrad:
"In the 1950s, Nikita Khrushchev offered the entire Kaliningrad Oblast to the Lithuanian SSR but Antanas Sniečkus refused to accept the territory because it would add at least a million ethnic Russians to Lithuania proper."
Amazing foresight on the part of the Lithuanians. There is no doubt that had there been 1+ million Russians in Lithuania for decades it would have created a very volatile situation upon the breakup of the USSR, and Lithuania could have possibly found itself in either Belarus' shoes as a Russian puppet state or in Ukraine's shoes as a target for invasion in the name of "protecting ethnic Russian's interests."
