Clizzy

Clizzy is a Femslash ship between Clary Fray and Isabelle Lightwood in The Mortal Instruments series.

Another Tumblr Account  One Tumblr Account "first one clizzy" Tumblr Account Number Three "clizzy will rise babe" "The show has made me ship them a bit" "what if clary had fallen for isabelle instead of jace"

Canon
In-series, Clary and Isabelle are nothing more than good friends.

Fanon
People often want Isabelle Lightwood to be bisexual because "she was never confirmed as straight" bi!Isabelle seems to be pretty popular.