Themes for wordpress are available every where on the web (24000 wordpress themes), but you need a SEO friendly theme. If the theme coding is not SEO friendly then it can effect your blog ranking in search engines. So you need to install only search engine friendly theme for your blog. Here are 5 wordpress themes are search engine optimized and free.
1. TechMaish Theme
Demo | Download
2. Hybrid Theme
Demo | Download
3. Daily Note Theme
Demo | Download
4. WP Perfect Theme
Demo | Download
5. Mimbo
Demo | Download
Hope you like the themes.