Hi!
I started to develop an application that makes freetext searching in KiCad libraries possible kicad-search .
Although project is in early development stage, it’s already functional. I started this project to solve my own needs, but thought other may be interested too. My preferrable OS is linux, but I believe it should work fine even in non-posix environmens. All suggestions how to improve the program are welcome 
Regards //Arvid
Having a standalone tool is very useful but have you thought about adding this functionality into KiCad itself?
No, I don’t believe that tight integration is always good idea, besides it could be challenging - KiCad is written in C++, while this application in python.