For me it has to be the following composers and my favourite piece from them on the side:
-Wolfgang Amadeus Mozart 1756-1791 (Symphony No. 25, Symphony No. 40 1st movement, Symphony No. 40 3rd movement)
-Ludwig van Beethoven 1770-1827 (Symphony No. 3 Eroica, Symphony No. 9 Scherzo)
-Johann Strauss I 1804-1849 (Radetzky March)*others I don't remember
-Richard Wagner 1812-1883 (The Ring of the Nibelung, Flight of the Valkyries, The Flying Dutchman)
-Bedrich Smetana 1824-1884 (Wallenstein's Camp, The Death of Wallenstein)
-Johann Strauss II 1825-1899 (The Blue Danube, Napoleon III March)
-Pyotr Ilyich Tchaikovsky 1840-1893 (1812 Overture, The Nutcracker, Swan Lake)
-Antonin Dvorak 1841-1904 (From the New World)*particularly the Allegro con Fuoco bit, so epic
-Gustav Mahler 1860-1911 (Symphony No. 2, Symphony No. 3, Symphony No. 5, Symphony No. 6)
-Richard Strauss 1864-1949 (Thus Spoke Zarathustra)*among others that I don't remember
-Daniel Alomia Robles 1871-1942 (El Condor Pasa)*made popular by Simon and Garfunkel
-Gustav Holst 1874-1934 (The Planets)*Mars, Jupiter, Saturn and Uranus if I had to choose
-Maurice Ravel 1875-1937 (Bolero)*only one I can think of but what an amazing piece
I could have included some other ones from the 1700's and 1800's as well but I forget most of the names like Vivaldi, Paganini, Bach, Salieri, Haydn, Schubert, Hummel and Handel I honestly have not listened to as much. In truth I prefer some of the more epic composers for their music like the ones that I listed.
There are also some modern film composers and of those I would throw in Nino Rota (Waterloo 1970), Enio Morricone (The Dollars Trilogy 1964-1966, Red Sonia 1985), Basil Poledouris (Conan the Barbarian 1982, Hunt for Red October 1990), James Horner (Mask of Zorro 1998, Troy 2004), John Williams (Star Wars 1970-2015 among many others) and Miklos Rozsa (El Cid 1961, Ben-Hur 1959, King of Kings 1961), Elmer Bernstein (The Ten Commandments 1956) and Alex North (Spartacus 1960, Cleopatra 1963).