Perhaps it would be a good idea to rename this thread to "Moscow Parks and Estates".
There are many, and most are off the beaten tourist path. Off the top of my head, only the big ones, in no particular order - Neskuchnyj Sad (Gorky Park) Sokolniki, Izmajlovo, Botanical Garden + VDNKh, Losinyj Ostrov, MSU campus and adjacent embarkment area (Vorob'jevy gory- Sparrow Hills), Serebriannyj Bor, Kolomenskoe, Victory Park (Poklonnaja Gora), Kuzminki, Kuskovo, Ostankino, Bitsa, Krylatskoe, and many smaller others. An attempt at a full list in Russian is here
and a much shorter in English - here
A Russian site on Moscow parks.
This one, Izmajlovo, photo by Bolik
, March 30 2008, is East of center. It is much bigger than shown here (1608 hectares). Clean, but the trails need work.
a couple of Russian links
This thread is far from covering what the park is, but this is typical of Moscow in general - it is hard to grasp the scope if you give just one shot.