I used LTP back in 2012, very useful:
Input 1 seed keyword.
Hit “Generate Keywords”
Bam a nice list of long tail keywords ready to use... about 10-15 minutes process saving hours and hours of work.
Then... not sure what happened, too much too fast maybe, and other big names were catching up.
Glad it is on AppSumo... bought it and it does what I need: saves me lots of time!

Thanks team!