Realme has updated some of its phones' sales listings in India with new color options. The devices in question are far from the OEM's newest offerings: therefore, this change may reflect how well they are selling, or need to sell in the immediate future, perhaps. The C3 is an example of these chosen few.
https://www.notebookcheck.net/Realme-India-adds-new-color-options-in-some-of-its-popular-phones.484847.0.html