This is potentially a vast question and not really suited to this forum.
"Third Party Tools" are tools, controls, utilities etc developed by companies other than Microsoft (if you are referring to Visual Studio). If the company you work for develops their own software, then "third party" could mean anything that they have purchased or downloaded versus anything written "in-house"
As to what they are good for ... that rather depends on what you want them for.
Some further discussion can be found
here[
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here[
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here[
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JQGrid is a control produced by TriRand providing ways of meaningfully displaying data - see
http://www.trirand.com/blog/[
^]
Finally - there is no concept of "learning" third party tools. Each requirement deserves it's own research. There is also no real concept of the "best tool" - it will depend on what you need for the job