…pencil?
Clearly in the mid-1980s this is precisely what people were dreaming of, judging by the sheer number of white fineliner sets around at the time.

Rotring, Staedtler and Faber-Castell each had their own all-white sets, containing three or even four pencils in the case of Rotring’s Art. 502 019 wallet.

These sets first appeared in Rotring’s 1986 catalogue and continued to be sold until at least 1990.
I am not certain when Staedtler and Faber-Castell began to sell theirs, but the 1988 Faber-Castell catalogue does contain a Contura-Matic L pencil in white.

What was behind this sudden craze for all-white pencils? If I had to guess, it would be the vogue for white suits epitomised by the character Sonny Crockett in Miami Vice, first shown on TV in 1984.
The coloured lead thickness identification bands on the white Rotring Tikky Specials even appear to to echo the bright accent T-shirts that completed the look.

May your days be merry and bright, and may all your fineliners be white!