Yoast is the best option if you are looking for WordPress SEO plugin. I personally prefer using Yoast SEO plugin. But, for your knowledge, I would like to name a few more options that you can prefer. One is SEO plugin by Squirrly and other is WordPress SEO Ultimate Plugin. Both these plugin has their own benefits and disadvantages. Talking about Squirrly, when you enter a keyword in the box, Squirrly will pop up images (the images are free from copyright fringement). It will also give you blog posts that use the same keyword and you can copy paragraphs of these in your own post. But, this will be duplication. So I suggest you write your own unique article. The software will analyze your text as you write and turn green when it is properly optimized. Once you have finished and published your post, the Squirrly Performance Analytics gives you an indication of their performance on social media and also their Google ranking. Squirrely will not override your existing SEO settings. You can refer this article. It has a detailed explaination. For Ultimate SEO plugin, here are some benefits that you cannot get with Yoast - DeepLink Juggernaut and Penguins: The Deeplink Juggernaut can provide automatic links between posts and pages that focus on a specified keyword, thus maximizing on-page linking relevancy. Simply enter your keyword, and Juggernaut creates the links. Google rewards sites that link like with like rather than those that link every page with every other.
You can make your links ‘Follow’ or ‘Nofollow’ on an individual basis. You can exclude certain pages from linking, such as Contact pages, and also the maximum number of links coming into each page. You can also control the maximum number of times a specified keyword can be used in anchor text. This is very important because overuse of the same anchor text can be punished by Google’s algorithm updates.