Love writing which ironically learned about three years ago that fountain pens and ink really help the flow.
Currently just browsing for iron galls or pinks, blues, reds and greens. If water proof even better.
For pens looking for things connected to the moon or stars or celestial bodies.
Did you know that you can compare the inks listed here with your own (i.e. only show those that the other owns that you don't) if you create an account on the site and enter your inks? You can sign up here.