Experienced Keyword Research for 400 keywords

hi, I own 40 plus websites and I am running out of ideas of doing keyword research. I need 400 keywords (Distinctive and Long trail keywords) that can reflect my business nature. Requirement as the followings: a. All the keywords should be Distinctive and long tails (at least 2-3 words) or phrase or questions b. All the keywords must be non competitive (although in my industry 95% of keywords are highly competitive). You need to find my niche or related keywords for me. c. Total of 400 keywords divided in 10 group for 10 websites. d. I am extremely picky of the words or topics. So previous experience or proven experience will consider first. e. This job must finish in 10 days and I will examine each keywords.