Well, I finally had time time to do a bit of brainstorming. I'm not exactly happy about all of the following quartets but I thought, I'd just post them all, maybe some of them are appealing to you:
indigo - bat / smoke, shadow / sound
amber - ant / wood / time, decay
pink - butterfly / coral / spring, growth, transformation
yellow - bee / brass / sun
green - snake / earth / health, life
ivory - elephant / bone / wealth
orange - fox / copper / stealth, trickery
crimson - boar, bull / blood / fury, strength
silver - fish / mercury / reflection, image
gold - lion / mead, spirit / rulership
colorless - jellyfish / crystal, diamond / vision
white - swan / ice / purity, death
black - raven / coal / intellect, speech
blue - fly / water / speed
grey - ram / stone / resolution, stability
maroon - deer / meat / hunt
cyan - dove / sky, clouds / dream, peace
ochre - scorpion / sand / space
brown - bear / skin, fur, leather / toughness, sleep
vermillion - squid / ink / change, mind, illusion
beige - turtle / lead / armor, protection
I've tried not to think too hard about mechanical implications and some of the pairings may seem a bit farfetched or even unlogical - but that's what you get when you're brainstorming
indigo - bat / smoke, shadow / sound
amber - ant / wood / time, decay
pink - butterfly / coral / spring, growth, transformation
yellow - bee / brass / sun
green - snake / earth / health, life
ivory - elephant / bone / wealth
orange - fox / copper / stealth, trickery
crimson - boar, bull / blood / fury, strength
silver - fish / mercury / reflection, image
gold - lion / mead, spirit / rulership
colorless - jellyfish / crystal, diamond / vision
white - swan / ice / purity, death
black - raven / coal / intellect, speech
blue - fly / water / speed
grey - ram / stone / resolution, stability
maroon - deer / meat / hunt
cyan - dove / sky, clouds / dream, peace
ochre - scorpion / sand / space
brown - bear / skin, fur, leather / toughness, sleep
vermillion - squid / ink / change, mind, illusion
beige - turtle / lead / armor, protection
I've tried not to think too hard about mechanical implications and some of the pairings may seem a bit farfetched or even unlogical - but that's what you get when you're brainstorming
