SAKURA
Sakura Pigma Micron (6-Pack)
Best for: Manga artists, graphic designers and journalers who need fine black lines

Copic
Nine black inking pens with pigment-based ink listed as waterproof, archival and photocopy safe, and compatible with Copic marker ink.
Best for: Copic marker users inking line art they want to keep
The Copic Multiliner 9-Pen Set is nine black inking pens from Copic. The pens use a pigment-based ink that Copic describes as waterproof, archival and photocopy safe.
The listing says the ink is compatible with Copic marker ink, and that the pens share the same ink and nib as Copic's Multiliner SP pens.
Based on the manufacturer's Amazon listing.
The listing says the ink is compatible with Copic Marker Ink, which matters if you color your line art with Copic markers.
Copic describes the ink as waterproof and archival. Archival ink is made for work you want to keep.
Copic describes the ink as photocopy safe, which matters if you copy or print your inked pages.
The listing says the ink is pigment based.
The listing says these share the ink and nib of Copic's Multiliner SP pens.
Look elsewhere if: you do not use Copic markers and want labeled point sizes. The Sakura Pigma Micron (6-Pack) covers 005 to 08 sizes.
Copic Multiliner 9-Pen Set
Choose it for: Inking under Copic markers
Choose it for: Six labeled points, 005 to 08
Staedtler Pigment Liner (6-Pack)
Choose it for: Metal-clad tips from 0.05 mm
SAKURA
Best for: Manga artists, graphic designers and journalers who need fine black lines
KOUSICOO
Best for: Doodlers, zentangle fans and comic beginners who want many line widths
TWOHANDS
Best for: Technical drawers, illustrators and journalers who switch line widths often
Ohuhu
Best for: Adult colorists who want brush strokes and fine detail from one marker