Btw, some of the mini cube 4-packs do the work for us, with colors that look beautiful together.
For example, on this Ellen Hutston page a few that caught my eye - and there are others:
(select at least 48 items per page)
https://www.ellenhutson.com/Search.h...ssortment-F628
Hero Arts Ink Cube Packs:
- Sweet
- Kelly's Outdoor Inks
- Lia Griffith Color Lights
- Coffee & Donuts - not that it's rainbow/ROYGBIV but the colors are so pretty together, at least for my taste.
While the 4-packs don't have every color you may want when you're going rainbow, they're a foundation, and just one more ink may finish it off.