Jean,
They come in other colours, such as green, or blue, both with white. Like anything with collecting they turn up in an ad hoc way, but these lamp bases are not uncommon.
Nigel
PS. I assume, in the absence of a photo, that we're talking of the thick, clear tall base with a slight twist down its length, and having a flared out base - designed by Angus Sillars (spelling from memory)? N.