Well Dash the problem is that even on that basis, something like Alteraeon would still count since with the mushZ pack there are more sounds than in most audiogames, and the same is likely true for other muds with dedicated soundpacks like Cosmic rage.
Then on the other side there are quite legitimate multiplayer games that just don't have many sound effects, heck the ucon games for Ios don't have any, and even games like lost cities or Quentin C playroom only have a few.
To make your list make sense, I would personally suggest splitting the games up by genre, eg, multiplayer action games, muds with soundpacks, multiplayer card or traditional games, multiplayer stratogy games etc.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)