Mobs Immune or Very Resistant to Root/Snare
Note: Most boss mobs are left off of the list due to high snare resistance. Mobs marked with a (?) are not 100% verified.

Old World

Stonebrunt Mountains:
Snowbeast & Other Titan Mobs

Kunark

Field of Bone:
Oracle Qulin

Trakanon's Teeth:
Crusader Vragor

Skyfire:
Nightfire Drake

Velious

Cobalt Scar:
Azureake
Bulthar Herdleader
Yvolcarn

Dragon Necropolis:
Bats

Luclin

Dawnshroud Peaks:
Age Old Rockhopper
Goranga Leader

Echo Caverns:
Xiliniov
Fireclaw

Fungus Grove:
Mutant Dregs
Mushrooms

Grey, The
Xakra Sei
Xakra Shah

Grimling Forest:
Sonic Wolves

Hollowshade Moor:
Sonic Wolves

Marus Seru:
Lightcrawlers (?)

Mon Letalis:
Spire Lord

Scarlet Desert:
Krean Flameweaver

Tenebrous Mountains:
Bats
Grimling Runner
Named Vampires

Umbral Plains:
Dark Assassins
Dark Masters
Gargantuan Zelniaks