Bonnie Hunter has tons of freebies on her site for scrap quilts.
http://quiltville.blogspot.com/p/free-patterns.html
Many bloggers also have free patterns or free BOM but once the BOM is over the pattern is no longer free.
As Kwilter said all the manufacturers have free patterns available for download on their websites. Some aren't free so you have to look to see if they are marked as such. Here are some links
http://www.robertkaufman.com/quilting/quilts_patterns/
http://hoffmancaliforniafabrics.net/...shop.php?a=pat
https://ttfabrics.com/projects/
https://www.andoverfabrics.com/FreeQuiltPatterns.php
http://www.windhamfabrics.net/cgi-bi...p/projects.cgi
http://blog.modafabrics.com/funfree/free-patterns/