Create a contact list of potential clients: up to 20 companies initially, more companies later

I am looking for someone to help me build a potential customer target list. The list will be the names of individuals in certain roles at certain companies. I will share with you what roles at which companies during a chat session. Initially, I want to give this project to the best candidate for the job, to give them an opportunity with a short list of 20 companies; with the potential of growing the number of companies to many, many more than 20 further down the track.