hi there..

http://www.patterninislamicart.com/
http://www.tilingsearch.org/

good books would be

The world of patterns
http://books.google.com/books?isbn=9810246196

376 Decorative Allover Patterns from Historic Tilework and Textiles
http://books.google.com/books?isbn=0486261468

Tilings and Patterns
http://books.google.com/books?isbn=0486469816

and you might want to check archive.org for some ornamental goodies

http://archive.org/search.php?query=subject%3A%22Decoration%20and%20ornament%22


cheers,
marco

http://www.westmaster.com/zidek/research/

http://www.tamabi.ac.jp/idd/shiro/muqarnas/default.htm

http://www.entrelacs.net/

with the programm at the bottom page of this site http://perso.orange.fr/hypatiasoft/F_index.html

My little try from an image by Lemo :)