Water/Nature:
Bog Beasts!
More seriously, how about Astral/Water?
- Personal Buffs! Body Ethereal + Personal Luck + Astral Shield + Quicken Self + Breath of Winter
- You know all of those beefy water summons: Krakens, Sea Serpents, Asp Turtles, Sea Trolls, oh my? Buff them, too! Ethereal Asp Turtles! Lucky Sea Trolls!
- Abominations!
- Underwater Mind Hunters that can't get shot by Seeking Arrows, toasted by Flames from the Sky, or sickened by Leprosy
- Um ... hold on a second....
- There are two nifty Astral/Water artifacts: Trident from Beyond & Nethgul.
- Did I mention Abominations yet?
- Power of the Spheres + Falling Frost (or Ice Strike, or Frozen Heart) spam
- That's all I got for now.
I guess it's not great synergy, but there are a few possibilities.