ahrefs.com is the best in my opinion

Backlink Watch
Open Site Explorer
Ahrefs SEO tools
Majestic
All of these tools are used for backlinks cheaking

Moz, ahrefs, majestic are good sources, but if you're searching for more backlinks then you have to go for premium member of these websites, so better go to Google Search Console formerly Google Webmaster tool.

Thanks,
Wrig Mark

Ahrefs one of the effective tool for checking backlinks but it gives complete results only for subscribers, so some other tools like backlinkwatch, ranksignals can be preferred.

I Just Want to Know How to check back links with URLs?

Backlinkwatch is best Free SEO tools to check the site backlinks.

In simple terms, back links are incoming links to a website or page. This means that the other website has a hyperlink "pointing" to your site. In terms of search engine optimisation, the higher the number of back links you have pointing to your site the better, especially if the site is particularly relevant to your niche.

As the number one goal of a website is to achieve traffic, i.e. people actually looking at the site, it follows that you must make the website visible. Generally speaking, to make your website visible, people must be able to find it when they search for keywords directly related to your product, niche, service or whatever else your website represents. Individuals tend to be seeking such information via the big search engines, whose operators have rather complicated algorithms to help them decide whether a certain website is applicable to the searcher's request, or not.

Ahrefs or Alexa is the best tool for backlink

You can use backlinkwatch SEO tool for website backlinks analysis.

You can use backlinkwatch tool.

For this Google webmaster tool is all you can get. Apart from webmaster you can also go for Ahrefs, Open Site Explorer, or backlink checker tool.