what is seo tool useful for seo in 2016?
 

please tell me :what is seo tool useful for seo in 2016?

Different SEO tools are there
1 Ahrefs
2 SEO moz
3 Keyword planner

These are the useful SEO tools :
Alexa
Ahrefs
Hootsuite

I still find google webmaster tools the best for seo

SEO BooK
Search engine visibility

web master tool
google trend
analytics
aref
moz
woorank
copyscrape
duplichecker

Can I know about the best SEO XML for sitemaps

You can use :
ahref , Mozbar , majestic , analytic , webmastertool , keyword IO , keyword planner
and check duplicate content : copy space , smalling check , duplichecker .. :)
Seo Yoast use WP

Mainly there are two important tools for the SEO which are,
Google Web Master or Web console and
Google Analytics tool.

Web Master and Web analytics which is the two main tool, can be used for the maintenance of the SEO.

Some of the best seo tools are:
Google webmaster
Google analytics
Keyword planner
Ahref.

These are the useful SEO tools :
Alexa
Ahrefs
Hootsuite

Some of the best seo tools are:
Google webmaster
Google analytics
Keyword planner