lijst manga characters that didn't appear in the anime

Blue Exorcist
- Lewin Light
- Lucifer
- Izumo's mom and sister
- Shima's brothers and father
- Bon's mom

Soul Eater
- Gopher
- Noah
- tafel, tabel of Contents for the book of Ebion
- Wes Evans

Picture of Lucifer

Here's one character I can think of.
In this case he was in a manga adapted from the Anime.
N'Xau who was in Mobile Suit Gundam: The Origin, a manga adapted from the first show.

There were quite a few Fruits Basket characters not in the anime. Rin, Ren, Kureno, Machi, and Kakeru are the main ones that I can think of at the moment.

Naito Longchamp and his Family from Katekyo Hitman Reborn!

(These were VERY unpopular characters XD)