Mesmer WvW Build
Check out stickied https://forum-en.gw2archive.eu/forum/professions/mesmer/Guide-WvWvW-Pve-Shatter-Cat/first
He has several different builds that are effective in WvW.
Vague question. What do you want out of your WvW? Ranged, support, heals, burst, condition? My advise is use whatever you’re using for general pve and that you enjoy playing. Other than that there are dozens of builds in the first 3 pages of the Mesmer forums. Give em a look through, you’ll probably find something interesting.
Black Ops supply line disruptions.