Insignia were in the original Guild Wars.
http://wiki.guildwars.com/wiki/Insignia
Why are they (Insignia) missing in Guild Wars 2?
In Guild Wars 2 we get prefixes:
http://wiki.guildwars2.com/wiki/Mighty#Prefixes
These prefixes are permanently fixed to weapons / armors etc and cannot be salvaged out.
I suggest that the Guild Wars 2 prefixes be made into Insignias.
We need more types of Insignias too.
https://forum-en.gw2archive.eu/forum/game/suggestions/need-more-types-of-prefixes-not-enough-prefixes-variety/first#post169797
Thank you!