Note: Kontakt instrument is included, picking non-Kontakt orchestra stuff is pretty slim. You can still use the 15 min demo or the "alternative way", if you know what I meant.

ONE - VSCO 2: CE

Samulis, Nimble and @Troisnyx 's creation. Probably the best free orchestra library in the wild. The only public domain and FLOSS library :(

Bonus: Etherealwinds Harp by @Etherealwinds

TWO - Mihai Sorohan Choir

Made by Sorohanro and MaestroRage

THREE - Palette Primary Colors

Pretty awesome Kontakt instrument for orchestra patches.

FIVE - Sonuscore FREE HD ORCHESTRA CHORDS & SUSTAINED STRING CHORDS

SIX - 8Dio Freebies

Err, non commercial, but nobody stopping you ;). Check out the Century Brass and Century String

SEVEN - Ensemblia

Little tool to mess around.

EIGHT - Embertone Ancient Voices, Imitate Strings LITE and Ivory Winds

NINE - Orchestral Rise Builder

TEN - @blackattackbitch SF2 collection

It wouldn't be a complete guide without mentioning BAB collection that helped countless people. His collection is the earliest orchestra stuff that many people, including me, relied on.

Have fun, y'all.