you forgot a major one that's also still running (though it's traded hands a few times)
Meridian 59 - Official Website
they went f2p also and are doing fairly well (especially since they, like all the other pre-UO mmo's, are generally completely forgotten about

)
I believe Nexus and TRO (2 other MMO's that came out before UO) are also F2P as well, though they were never terribly popular in the US anyways (Nexus has a good sized fanbase, but much like when it was new 90% of it is korean, similar to lineage)
Edit: damn, nearly forgot a VERY important example, Tibia, another pre-UO mmo. It went F2P also a LONG time ago and has kept a very steady playerbase, they currently have 77(!) active shards and peak at around 20-30k users online concurrently (active playerbase is estimated around 50-60k players, which when you consider the game is older than UO and relatively unknown...they still have a higher active population than we do...)