The Google Keyword Tool is SUPER helpful for building a foundation for your keyword research strategy. At the end of the day, these search numbers are coming straight from the horses mouth. You can filter down to a hyper-local level and see which keywords are getting the largest search volume. Plus, with it’s integration with PPC you can get a quick idea about commercial intent by looking at the bid and competition metrics. How much are people bidding on KWs, higher = more likely to generate a return. Usually its aligned with search intent. That said, the trending data is a little less reliable. I would still use Trends to analyze the popularity/ seasonality of KW search volume.
Keyword research is a practice search engine optimization (SEO) professionals use to find and research alternative search terms that people enter into search engines while looking for a similar subject. Search engine optimization professionals research additional keywords, which they use to achieve better rankings in search engines. Once they find a niche keyword, they expand on it to find similar keywords. Keyword suggestion tools usually aid the process, like the Google Ads Keyword Planner, which offers a thesaurus and alternative keyword suggestions or by looking into Google Suggest.[1]
The limit on manual keywords could be higher.  I personally wish we could input 10,000 keywords at a time, instead of 200.  However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input.  Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).

The only problem is that you can’t possibly laser-target every ad to the search query, and your landing page will definitely not be as targeted as it could be either. Not even dynamic keyword insertion (DKI) would help, because who wants to click on an ad with the headline of just “Bounce House”? Let’s just say it gets tricky, and you’re a little lazy if that’s all you do.

"This is the only keyword research tool that I recommend. The ideas, inspiration, and content longtails you will get for your niche topic are going to result in you producing a page of content that is more than going to pay for this tool. And as they are Google's database then we KNOW that these terms are being searched by a decent volume of peeps every month. It's a goldmine dudes."
The SEO market has been recording a lot of advancements in the recent past. The world has thousands of keyword research tools and it’s hard for you to grasp all of them. Some of them come free of charge while others have to be paid. There are so many free keyword tools that generate excellent results in the various search engines. This article eases your work by presenting top ten free keyword research tools you can find in the market. You can use any of them depending on your SEO needs and nature of industry.

In a nutshell, Long Tail Pro helps you quickly find keywords in bulk based on a seed keyword that you input.  In addition to returning hundreds of related keywords, the tool also shows search volume (monthly search volume), advertiser bid, number of words, rank value, and my favorite Keyword Competitiveness (helps you judge the competition and keyword difficulty).