So after collecting a large amount of Echos, I've learned two things.
1: Blue seems to be the Most Common
2: They're Pretty Fun to Mess around with.
So I did some tinkering with them, and turns out you can bundle them together, they sorta combine in one spot and make different colors and such.
Here's a few Screenshots I've taken showing what I've come up with so far.
Combinations of 2 colors.
Starting From the Top Row.
Magenta (Red+Blue) Blue
Yellow (Red+Green) Cyan (Blue+Green) Green
Goldenrod (Red+Gold) Pink (Blue+Gold) Neon (Green+Gold) Gold
I Feel Like adding the Gold echo gives a neat Little Aura.
These Next Few Show 3 or more Echos Combined.
Red Blue Green
Red Blue Gold
Blue Green Gold.
All 4 Combined.
So that's what I have So Far, Feel free to Post screenshots of things you've done with Echos.
You can combine as many as you want, And In Different amounts. If you got excess here are some tips.
Be Sure to take Screenshots at Night Time for the Full Effect.
Combine varying amounts of 2 Echos to create more dynamic colors and Auras.