Here's a concept to run up the flagpole. Magic swords must be named after a rock ‘n’ roll song, preferably metal. Maybe if a song becomes sufficiently awesome in our dimension it hardens into a blade in the D&D universe. Or maybe I just want an easy way to give cool names to swords.
Rainbow in the Dark - Possesses Prismatic Spray powers that only work underground or at night. Each color can be used once per day. The red ray is available to wielders of 2nd level or above. Another color becomes available every other level. (I.e. you must be 14th level to get access to all 7 colors.)
Seven Seas of Rhye - Vorpal against anyone who has betrayed the wielder.
Ace of Spades - Wielder can inflict d6 damage on self (blood runs from hands) for an additional +2 to hit and double damage.
Cry for Eternity - A.k.a. the Blade of Unrelenting Vengeance. The wielder cannot be killed until they have achieved revenge or they drop/sheath the sword, but rather can shuffle on as a revenant-like shell of burning hatred.
Heaven and Hell - Can cut through illusions, dispelling them instantly. Double damage to anyone who has ever lied to the wielder.
Hand of Doom - Any humanoid slain by the sword rises as a ghoul. The wielder commands the last victim to rise as henchghoul.
I think that turned out pretty good. I'd probably have never written a magic sword tied to social situations like betrayal or lies without this song-based prompt. I'd probably make all the swords written under this system +1 in addition to whatever other powers they possessed.
Anybody else got any ideas for swords based on songs?