I decided today to list off all the keyword research tools out there that are very popular or very interesting in their own right. In some ways I'm making this pages mostly for my own reference because I tend to forget how I came to know one tool from the next and what is actually different about it from the others.
I've also included below whether each tool is a paid or free model. So have at it. If I missed something then please let me know.
This is a free tool introduced to me by Zeke over on this thread on The Pond. To quote Zeke this tool "gives you relevant suggestions for your keywords and tells you how tough the competition is." It doesn't just list of related terms like Google's keyword Planner or similar tools, it suggests other keywords independently. It's all web based. There's no download but you do need to setup a free account with login.
Google's Keyword Plannerhttps://adwords.google.com/ko/KeywordPlanner/Home
This is Googles tool for Adwords account holders. It's the keywords from the horses mouth and many tools use this as their foundation for research... as you surely know already.
This is another tool made by a friend over in The Pond. It was the first of it's kind when it was released. It's a Google autocomplete scraper with plenty of wildcard options. I love this type of tool. It basically automates a lot of the kind of research I like to do by hand. There is a paid and free version of this and it's a downloadable program that runs straight from an executable file. Not exactly handy for mobile devices but seriously, who really works on a tablet or phone? :/
This is a super sweet program that is web based (no download). It is a subscription and has a free trial feature and an affiliate program. I used to use this a lot but wasn't using it enough to keep sunscribing but it is extremely valuable if you are creating tons of content. It was introduced to me by Judy over at the Pond. She is killing it online and she regularly says that this is the only program she uses to find keywords. She also pumps out way more content than I ever have so it's her bread and butter. Like keyword researcher this tool not only mines for keywords but also gives you competition analysis on the fly which can really speed up your work flow.
Long Tail Pro / Platinumhttp://www.longtailpro.com/
This is the wildly popular keyword research tool used and abused by every niche marketer/blogger out there. I'm not 100% sure if it's because it's amazing at what it does or that it has a nice affiliate program. :/ Believe it or not I've never used LTP before. Lots of people swear by it so it can't be bad, I'm just not sure it's the best; but then again what do I know having never used it. The software has a one time use fee for limited features and an additional subscription for the added features. It's the priciest tool on this list.
Stealth Keyword Diggerhttp://www.stealthkeyworddigger.com/
This is a one time fee purchase for downloadable software. It's a lot like LTP but cheaper. It takes a seed keyword and looks at the top closely related keywords then uses those top keywords to scrape lots of search engines to generate tons of long tails. You can then use that info or narrow down the list by important the list into their companion software: Stealth Keyword Competition Analyser (also a reasonable one time fee) to narrow down which keywords are worth going after based on estimated traffic and competition levels. These two programs were first introduced to me by Claire aka Skeffling of SkefflingMakesMoneyOnline.com, also a member of The Pond.
Keyword Optimizer Prohttp://www.keywordoptimizerpro.com/
Yet another free keyword scraper of autocomplete search boxes. This one is a lot like the other scrapes that have few bells and whistles. It's simple and free and can give you a bunch of additional keywords that other scrapers miss. Just another free tool to find a few extra hidden gems.
A free no bells and whistles Google autocomplete scraper. It's web-based. This is as basic as it gets which is sometimes all you need. This was introduced to me by Hannah Gold, an avid and long time friend from InfoBarrel. She's active all over the place and runs a girl scout blog.
For now that's it. As I come across other tools I'll add them here or expand on my mini-descriptions. In time maybe I'll even do full fledged reviews but I don't make any promises.