There are lots of resources that you can find on google. But According to me, the best SEO resource is Search engine land, SEO book, SEO round table, Seawind Solution, Etc. If you want to hire a best Digital marketing services to increase your business or website in major search engines,then you can visit at http://www.seawindsolution.com/search-engine-optimization-company/
There are so famous bloggers who post amazing content related to seo. Follow them and learn. Google is the best source learning anything today.
Some bloggers i follow are:
- Neil Patel (Blogs: Neilpatel and quicksprout)
- Brian Dean (Blog: Backlinko)
- Rand fishkin (Blog: Moz)
- Danny Sullivan (Blog: Search Engine Land)
- Bruce Clay
- Eric Enge
- Barry Schwartz (Blog: Search Engine Roundtable)