there is another one that was a massive failure and is 10ish years old but still has like 1k players on it. Its MEDIEVAL with viking hints/specially if you buy the armor skins for viking looks.
But its not completely VIKING, just feudal ages.
Called LIFE IS FEUDAL.
or
Conan Exiles.
Same issues, not a viking game, but got the posibility to look like one. And is survival/base building.