Played Greyjoy very successfully in the CCG, looking to start the LCG. The options for GJ are limited, but here's what I've come up with:
House: (1) Greyjoy
Agenda: (1) Kings of Winter
Plots: (7)
Summoning Season
Building Season
The Winds of Winter
A Time for Ravens
Rule by Decree
Marched to the Wall
Valar Morghulis
Characters: (22)
3X Island Refugees
3X Carrion Birds
3X Wintertime Marauders
3X Bloodthirsty Crew
1X Samwell Tarley
1X Fishwhiskers
1X Maester Wendamyr
1X Wex Pyke
1X Alannys Greyjoy
1X Theon Greyjoy - A Change of Seasons
1X Asha Greyjoy
1X Dagmer Cleftjaw
1X Balon Greyjoy - Kings of the Sea
1X Euron Crow's Eye - Kings of the Sea
Locations: (24)
2X Refurbished Hulk
3X Iron Island Fiefdoms
2X Bloody Keep
3X Sunset Sea
1X Street of Steel
1X Street of Sisters
3X Iron Mines
3X Naval Escort
1X Aeron's Chambers
1X Longship Iron Victory
1X Longship Foamdrinker
2X Scouting Vessel
1X Den of the Wolf
Attachments: (8)
3X Support of Harlaw
2X White Raven
2X War Horn
1X Driftwood Crown
Events: (6)
3X Assault of the Kraken
3X Risen from the Sea
It plays simply like old-school GJ control: use cheap, efficient characters to win challenges early, use a combination of Warship pump, Attachments, and a few characters to make your opponent overextend to counter, deny resources, and use plot deck to control board/hand and for search. I'm happy with most of the current selection of cards, although I miss Promo King's Landing with a passion as well as the older, more efficient GJ location control.
I'm open to suggestions, but keep these things in mind: I won't run multiple copies of a Unique location/character, it's a waste when you're running search and saving, and I like having a ton of locations, especially warship pumps... other than that, go nuts.