SweetData.io is described as 'data marketplace allowing to search, buy, sell and download datasets aimed for machine learning and big data purposes. Data is the new oil, but we need pipelines. SweetData'. There are three alternatives to SweetData.io for Online / Web-based. The best alternative is Kaggle. It's not free, so if you're looking for a free alternative, you could try Driven Data or Numerai.
Kaggle is a platform for data-related competitions. The platform allows companies, researchers, government and other organizations to post their modeling problems and have data professionals and researchers compete to produce the best solutions.
Online data science challenge platform for world's biggest social issues/problems, where a global community of data scientists competes to come up with the best statistical model for difficult predictive problems that make a difference.
Earn cryptocurrency in weekly data science competitions. Because Numerai abstracts its financial data, data scientists do not know what the data represents and human biases and overfitting are overcome.