Two regular expression tools that have similar features for those programmers who deal with regular expressions regularly 
Another awesome regular expression resource I found was http://www.rexegg.com/. I haven’t gone through it all but I’ve found it quite extensive for regular expression information.
I’d like to second @erictleung 's recommendation of Regex 101 as a good tool for debugging your Regular Expressions. Its helped me find several sticky bugs.
Another one that is very good, with concise help as tooltips is http://regexr.com/ . I’ve used regex 101 before too. And maybe the regex tool I’d pay for is https://www.regexbuddy.com/
Thanks for the great resources!!
I haven`t worked with them much so far, apart from algorithms, but I found this helpful
http://leaverou.github.io/regexplained/ Here is the movie when the author is using it explaining regex https://www.youtube.com/watch?v=EkluES9Rvak
I like regexr and even SublimeText has a regex engine when you do a search or a serach&replace.
I really like http://scriptular.com - it’s wonderful and has completely removed my fear of regex!
Oops, just saw @erictleung’s regex101 suggestion…which looks better. Protip: read posts before commenting 