I do a scrapebox blast of 20K backlinks blog comments feed rss and ping just give me a keyword based on your niche, for example, if your site is about blog, i will find website about blog, You will get a mix of dofollow and nofollow links, links with high page rank and low page rank. The large variability of links will make this blast appear to 100% natural to all search engines, all link is natural not auto-approve. Thanks