There is a an article in "Chicago Evening Post" that is declaring Presale.Ventures platform as World Largest Seed Funding Platform based on  Blockchain Startups. I think its justify to declare it as a leader as its the first seed funding platform for investors and startups worldwide to meet directly.
You can read more on it at
http://chicagoeveningpost.com/2018/03/22/presale-ventures-world-largest-seed-funding-platform-for-blockchain-startups/
loretta75