From chapter 1 to the end of the first season:
All the symbols and eyes are green
The only one who has a different eye color is Gax with red eyes
scorch:

Omnitrix on chest, same height as you

quad punch:

Same height as you
filth fly:

Same height as you

rage: green shorts and a black and white sleeveless hoodie that is unzipped same height as you
bushwhacker :

Same height as you

wreaking ball:

Same height as you
Brawlasaurus:

Same height as bens fourarms
Membrane:

shrapnel:

Green eyes, same height as you
Technologic:

Same height as you
Speed demon:

Omnitrix on chest with white stripe, same height as you
Slapback :

Gax:

Shock rock:

Same height as you
Overflow :

Same height as you