Wow, congratulations on making it so far with only 30 Monster Boxes. I'd have gone crazy.
You have some good units, but not a lot of synergy. Things that stand out, you have some decent boosters, but not enough units to use them with, probably because you've had to trim units with. If I had your units to work with, I'd probably go dual-color red /green or straight red.
If I had your units in their current state, I'd probably go
Red:
Leader: Echidna
Agdoraru (your level 18 dragon)
Dino Rider
Goblin Warrior (Get one, they're easy to farm!)
(open slot)
Your open slot can either be an ogre for more hit points, ruby carbuncle for healing, your pyrodemon / lil' red for more attack, or a red knight for armor break.
Once you've evolved your Agodraru into a Flairdrall?, you'll be set for some crazy orb-changing shenanigans.
I'd probably go
Red / Green
Leader: Echidna (or Dino Rider if you go demon-heavy or Flair for anti-red / green)
Dino Rider
Flair
Green Mystic Knight
(Utility)
Your helpers should probably be red-boosters or healers.
Just my take.
Upgrade your box!