𝘈𝘣𝘰𝘶𝘵 𝘞𝘢𝘭𝘵𝘦𝘳 𝘒𝘰𝘦𝘯𝘪𝘨 𝘐 𝘬𝘯𝘰𝘸 𝘭𝘪𝘵𝘵𝘭𝘦, 𝘣𝘶𝘵 𝘸𝘰𝘶𝘭𝘥 𝘩𝘢𝘱𝘱𝘪𝘭𝘺 𝘭𝘦𝘢𝘳𝘯 𝘮𝘰𝘳𝘦.
Walter Koenig did some voice work for the game Star Trek Online around 2016. Something else that comes to mind is that he played himself in an episode of Futurama that aired around 2002. Beyond that I know little else.
keonig was in a couple of episodes of ‘the starlost’, a short lived series with a great premise, but lousy execution. it starred keir dullea (sp) who also starred in ‘2001: a space Odessey’