Less than 3mm in width is a pretty low bar.
Just doing a cursory scan of my collection, I can count the following Spyders (22 of them) at less than 3mm in width and there are probably more that I don't currently own or never owned (like the Balance, Catcherman, Kopa and Silverax that I've previouslyowned/sold which would make at least 26):
Ayoob
Calypso
Centofante 3
Des Horn
Hanan
Ikuchi
Introvert
Karahawk
Kiwi
Mantra 1
Mantra 2
Mantra 3
Pattadese
PITS
P'Kal
Positron
Shabaria
Stretch Gen1
Terzuola Slipit
Terzuola ATS34
UK Slipit
Watu
Mostly smaller folders and fighting knives with the exception of the Calypso (from which I believe that the Caly series was derived) which is a "big" knife (4" blade and micarta scales) and a very cool knife to own, if you don't have one already.
It's one of my favorites from my small sub-collection of vintage Spyders.