They did only make one expansion ‘Rise of the Godslayer’.
The other content they put out was all listed as Adventure Packs. They’ve done ‘The Savage Coast of Turan’ which was a movie tie in to the Jason Momoa Conan movie,
The ‘Secrets of Dragon’s Spine’ was part of the original pre-F2p AoC game that was spun off into an adventure pack. Those that had a sub in the pre-F2p period had the pack gifted to them automatically. But like with many things it was a hit and miss affair with some getting it, some not, but getting it after contacting customer support and others SOL.
And finally the ‘Shadow of Vanaheim’ pack.
The only other items of note under the ‘new content’ concept was 1 special PvE limited time server, 1 special Pvp limited time server.
Plus 2 new modes of play. The first was the ‘Unconquered’ mode where you started a new character on one of the existing servers and saw how high of level you could make it without dying. Getting various badges and vanity gear every so often. And the ‘Onslaught’ mode which is a wave fighting game. Both of those are still active and the dev’s have said they’ll always be in game from now on.