Sorry for the triple post, I also like the idea from Angry Dave for the frozen arrow:
[CR1] Water Arrowhead = Arrowhead + Water Bottle [CR3] Frozen Arrowhead = Water Arrowhead + Blank Air Spell
At work (shh, don't tell my boss ) so I can't double check in Engine, but I believe the Water Arrowheads don't even exist in the game, there's no art or asset for them. The arrow itself does, so we could make recipes that skip the head step... if the arrow is even that useful. To be honest I picked one up and have never had an occasion to use it. If it works similar to the rain spell I could see how that would be actually really useful, but my read is that it just extinguishes a single light source like a candle?