Since AoS there's been
Samurai Empire (Ninja & Samurai, Tokuno facet added)
Mondain's Legacy (elves as PCs)
Stygian Abyss (Gargoyles as PCs, Ter Mur facet added)
(and the High Seas "booster pack", that is an add-on - only important if you like fishing and ships, or want to wear one of the Corgul loot pieces - it comes with expanded storage for your house as well)
All existing accounts are upgraded through Mondain's Legacy. Trial accounts are ML (minus the stuff people used to abuse them for scripting). Since so much loot and crafted gear is currently dropped/created using SA, and won't be wearable by non-SA accounts.
The two choices are
1. Reactivating an existing account (which will be a ML level account) and upgrading to SA. You'd have to start paying from day one, but you'll have a bunch of finished skills to rearrange. They finally introduced soulstones as a 1-year vet reward choice (account-bound, so you have to claim them yourself), so you can swap skills between characters. There are also soulstone fragment tokens (5 uses), craftable 1-use soulstones, and (if you have the money to blow) soulstone tokens that can be bought from the store, or were given as awards from some of the expansions. If you get a soulstone from someplace other than your own vet rewards, it either needs to be a crafed 1-use one, or still be in token form when you buy it.
2. The other choice is just starting over with a SA new account, and the 30 days that come with it.