GPO5 adds the old GOS library, which includes some Col Legno variants for tutti strings. 

It also has more variations of pizzicato, and some extras like sul tasto and riccochet (probably more, but I forget).

Some of the extra articulations are't included in the KS variants of an Instrument, but it's possible to channel hop in most hosts and access them, and if your host can't do that, I can teach you an easy hack where you'd put a keyswitch to an empty layer in both sfz files and switch between a couple of Instrument Slots set to the same channel).