dr-archeville:

Ancient & Magickal Alphabets

Celestial Alphabet/Angelic Script, Malachim, and Passing the River were made up by 16th century German alchemist/astrologer/lawyer/magician/occultist/soldier/theologist Heinrich Cornelius Agrippa. Theban was created by 15th century German cryptographer/historian/lexicographer/occultist/theologian Johannes Trithemius, one of Agrippa’s teachers. The Alphabet of the Magi was created by 16th century Swiss German alchemist/astrologer/botanist/occultist/physician/toxicologist Theophrastus Bombastus von Hohenheim (aka Paracelsus), another of Trithemius’s students, who rejected Agrippa’s magical theories.

Those, and the two Tolkien made, are entirely fictional and are good to use in most any context. All the others are real alphabets from real cultures — some still used today — so be VERY aware of and careful with them.

More writing systems can be found at Omniglot.