Do you know about the Swab Shop at Goulet Pens? This is a section on their site where you can view swabs of ink colors by color grouping across brands, all the swabs for a particular brand or even try out an interactive swatch tool and then immediately add a sample or bottle to your cart. Looking for the perfect lipstick red ink or, in my case, the quintessential lemon-lime green? This is the best way to find it.
(photo from Goulet Pens in the Black Swab Shop section)