Aside from the
Brotherhood of Blood covenant...
The Blue Sentinels which invade the world of the guilty (BoB covenant). This covenant also has its own arena to duel in at the cost of
Tokens of Virtue. That would be my only con.
Dragon's Remenants is a summon PvP. Where you leave summon signs to be summoned and duel.
The Rat King covenant which allows you to traverse the
Grave of Saints &
Door of Pharros and combat grey spirits, which are people who are not part of the covenant that enter the area when you are wearing the covenant's corresponding ring.
Bell Keeper covenant A.K.A.
Bell Bros are similar to the
Rat King covenant. The difference being that you are teleported as a dark spirit to one of the bell locations when a player trespasses in the territory.
With those final two mentioned covenants, you are defending something.
Rat King is the bonfire and
Bell Keeper is the lever to ring the bell.
As for pros and cons, that is entirely what you want from your PvP experience.
Bell Keepers tend to gank a lot.
Rat King is a 1v1 with NPCs at your disposal. Aside from that, it is very opinionated.
Hope that's what you're looking for! :D