Aleevi, Tue, Sariki, Brainn, Yennefer, Corina, Xyliana.
I don't know the healers form guilds like Grey Order, Insight, BRC, Sith Dominion etc but I think there would be a lot to mention there.
I don't agree "a little" with the first 3 places of the OP, and " a lot" with the last 2. I mean, BRC is an AWESOME guild when it comes to PvE, but (no offence guys) not top 5 when it comes to PvP. The first 3 I would just swap places a little bit, but yeah, they are good pvpers.