Kaywa Blog supports every imaginable char, which is defined in utf-8 (displaying them depends on your font, it worked on my Mac).
But don’t ask me, what I wrote 😉
Hiragana
にま
Katakana
ッルピ
and also
Arabic
صأؤ
Hebrew
ציװפ
Cyrillic
Исшэ
Greek
Μαχΰ
Thai
ทสฤภ
and many more 😉