I like drawing with pen and then adding watercolor washes - meaning that I need a reliable, waterproof ink pen. I'm not ready to try fountain pens, so I collect pens to try whenever I'm in an art supply store.
I usually use Pigma Micron or Zig Millenium pens in 01 and 05 sizes on my Fabriano Artistico soft press paper. In this sketch I used a Zig Millenium pen to draw my 4 new pens, and then applied watercolor several minutes later. I made happy faces to "paint" with water for another test of the ink.
I was very surprised that my Zig millenium pen was the one that lifted the most with water. The other 4 did reasonably well in my test. Now I just have to remember where I bought them! And which ones were recommended to draw over acrylic paints.