Disclaimer: I write down my business ideas that I can implement in a day or in the worst case less than a week. The principle is to figure out something simple but still useful. I may do or not do them in the future but I write them down to offload them from my head to make space for other ideas.
Idea: send email marketing e-mails from Gmail.
Hire: someone who wants simple email marketing tool.
Indirect Competitors: any decent e-mail marketing tool like Mailchimp, Omnisend, Wix Email Marketing and etc.
Why I think I can do it fast: I think about minimal version not fully blown email marketing tool.