I have a link attached to the words "greek characters", but I am going to type them here just in case it doesn't help much as an image.
See on wikipedia for details and here: Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ τ υ φ χ ψ ω ς.
Thanks!
Edit: just noticed you meant only "special characters". Sorry for misreading your message. What would make a character special?