This list is subject to change. Any translations (especially Russian songs) are sometimes done by me and hence will not come up with results on google. The translations may also be wrong.

List:
Russia:
Prayer of the Russian People
Preobrazhensky March
Dark-eyed Cossack-girl
Kuban Regiment March
Song of the Volga Boatmen
Cap Song
The Clouds of Shipka
Korobeiniki
Stenka Razin
My Beloved Country
People's Avengers
Yablochko
Slavianka
March of the Siberian Rifles
Polyushka Polye
The Thunder of Victory
Tachanka
In the Garden
Katyusha
Säkkijärven Polkka

Soviets:
Moscow Nights
Soviet Waltz
The Cliff
Evening Bell
Nightingale
The Patriotic Song
Piloty
Bombers
Along the Peterskaia
Anthem of the USSR
The Sacred War
My Army
We are the Army of the People
Song of the Soldiers
Polyushka Polye (ver 2)
Katyusha (ver 2)
March of the Red Cavalry
Tankers' March
Unified Victory
March of the Guards' Mortarmen

Germany and Austria (peace):
Erlkönig
Leichte Kavallerie Overture
An Der Schönen Blauen Donau
Ode an die Freude
Havok
Moonlight Sonata
Sarabande
Ride of the Valkyries
Toccata et Fugue
Lacrimosa
Ave Maria

Germany (War):
Preussens Gloria
Westerwaldlied
Die Wacht am Rhein
Panzerlied
Königgrätzer Marsch
Pariser Einzugsmarsch
Kreuzritter-fanfare
Defiliermarsch
Alte Kameraden
Wir lagen vor Madagaskar

Austria (war):
Unter dem Doppeladler
Radetzky Marsch
K.U.K. Marsch
37er Regimentsmarsch
Gablenz-Marsch
Bellmond-Marsch
Hessenmarsch
Regiment sein Strassen zieht
Ein Regiment von Ungarland
Alpinjäger Marsch

China in general:
Mu Guiying Takes Command
Emperor of Qinglonh
Blossoms of Spring
Dragon
The Dream of Love
Countryside Ballad
Ballad of North-Henan
Tortoise
The Moonlight Reflection on Erquan

Qing:
Song of Beiyang
Cup of Solid Gold
Song of the Beiyang Fleet
Tai He
King Qin Breaks the Front Lines

Republic:
Going for a Battle
Indomitable Spirit
Ambitions in the Sky
Heroic Warriors

PRC:
Huang Pu's Soul
Learn from Lei Feng's Good Example
When the Day Comes
March of the PLA
Anthem of the PLA
Three Rules of Discipline and Eight Rules of Attention
Soldiers Belong on the Battlefield

Bavaria:
Augen geradeaus
Einheitsfrontlied
Jung sind die Linden
NVA anthem
Unser Panzerdivision
Auf Proletarier
Auferstanden aus Ruinen
Steigerlied
Lied vom Vaterland
Warschawjanka
Arbeiter von Wien
Der Schlimmste Feind