First good longsword is
Arguably the most common basic weapon is Heavy Mace, I had all the variants of it, from basic to elemental, +3 and +5.
Also 150 hours into the game I finally found unique +4 bastard sword lol.
act IV where you search for 3 witches. Its +2 adamantite with extra +2 if you rage. Then you can buy +4 weapons, and I found +4 sword that gives some protection from mind effects.
Arguably the most common basic weapon is Heavy Mace, I had all the variants of it, from basic to elemental, +3 and +5.
Also 150 hours into the game I finally found unique +4 bastard sword lol.