I need a good data structure collection for Unity, where can I find it?

I need it in c#.

C5 Generic Collection Library seems to be very complete, but it does not work on Unity. Any suggestion?

Use System.Collections.Generic plus System.Linq and you’ll have an awesome collection toolset that is supported in Unity.

What you miss from there that you need?

Also, what keeps you from using it in Unity if you have access to the sources of C5?

C5 now works with Unity3d - GitHub - sestoft/C5: C5 generic collection library for C#/.NET