Standard Assets (for Unity 2017.3)
Unity Technologies
★★★★★
Free Download

Free Platform Game Assets
Bayat Games
★★★★★
Free Download

Oculus Integration
Oculus
★★★
Free Download

SteamVR Plugin
Valve Corporation
★★★★
Free Download

Sunny Land
Ansimuz
★★★★★
Free Download

Nature Starter Kit 2
Shapes
★★★★★
Free Download

TextMesh Pro
Unity Technologies
★★★★★
Free Download

DOTween (HOTween v2)
Demigiant
★★★★★
Free Download

"Unity-Chan!" Model
unity-chan!
★★★★★
Free Download

ProBuilder 2.x
Unity Technologies
★★★★★
Free Download

Unity Particle Pack 5.x
Unity Technologies
★★★★★
Free Download

Unity Particle Pack
Unity Technologies
★★★★
Free Download

Basic Motions FREE Pack
Kevin Iglesias
★★★★★
Free Download

Terrain Tools Sample Asset Pack
Unity Technologies
★★★★★
Free Download

3D Game Kit
Unity Technologies
★★★★
Free Download

PUN 2 - FREE
Exit Games
★★★★
Free Download

Space Robot Kyle
Unity Technologies
★★★★
Free Download

Realistic Tree 9 [Rainbow Tree]
Rakshi Games
★★★★
Free Download

Terrain Textures Pack Free
ALP8310
★★★★
Free Download

Fantasy Forest Environment - Free Demo
TriForge Assets
★★★★★
Free Download