Ping-O-Matic - Service to update different search engines that your blog has updated.
KeywordTool.io - KeywordTool.io is the best FREE alternative to Google Keyword Planner and Ubersuggest. It uses Google's autocomplete feature to get over 750+ long-tail keywords for any given query.
TotalPing! - Promote your blog with TotalPing!
Google Trends - Explore Google trending search topics with Google Trends.
PingMyLinks - PingMyLinks is one of the oldest websites in the internet marketing industry that you can use to index your websites and blogs.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition