Usually, I think you need to find a particular piece of cc that comes with more swatches. If you search "The Sims 4 Base Game hair/eye Recolours" (or other packs) on google, you should be able to find cc which will add more options to the existing content. I hope this helps, but I personally don't use this type of cc, so you may have to go about it another way.
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https://wildlyminiaturesandwich.tumblr.com/tagged/wmshairrecolours
https://noodlescc.tumblr.com/tagged/sims_4_hair_recolor
eyes:
https://wildlyminiaturesandwich.tumblr.com/tagged/wmseyes
https://aveirasims.tumblr.com/downloads
http://pyxiidis.blogspot.com/p/downloads-overview.html