Is there an oveview of organizations support of segwit/segwit2X?
First of all, Segwit and Segwit2x are two different things. Segwit has already activated, Segwit2x has not. Please do not conflate the two.

https://coin.dance/poli and http://segwit.party/nya/ list the positions of various companies and project's on Segwit2x although they are not always accurate or clear.