Sharedcount sucks! I tried it on several domains and every time it comes up with outdated stats.
If we talk about online SEO tools, I should recommend http://colibritool.com. We use it for few months and we can say that it looks and works pretty well. It has Google Analytics integration, keyword suggestions, conversion measurement and some more. They are not free but they have trial plan so you can test it ;)
I see nothing free at Ontolo.com, but their services seem good.
http://www.freekeywords.wordtracker.com/keyword-questions doesnt work any more
I used a free version of SEO PowerSuite tools. The tools can handle tons of important SEO tasks: keyword research, rank checking, link building, etc.
The only disadvantage of the free version is that it can't save your projects. Purchasing the paid license solves this problem though
Microsoft SEO Toolkit (free) is my killer on page optimization tool. It beats screaming frog hands down.
Then the usual - majesticseo.com, semrush.com etc
Trim 2 root
This is great! Thanks
ahrefs.com has a (limited) free account.
Raven Tools and Colibri Tool.
Try this one http://inbound.org/articles/view/onpage-seo-tool-check-web-on-page-seo-score-for-free
Great! Head over to login and use your credentials there