A lot of people use the same username on Fiverr and Twitter. So go scrape some usernames off Fiverr related to your niche. Then make some Twitter accounts and follow those people. Finally, spam out your Fiverr gigs to them. Pro tip: Put your Fiverr link in your description (not the website field) in Twitter - that way when you follow them they will get that link in their inbox with whatever your description says.