A friend of mine at openaircollective.cc made this map that lists various sites. I think it is too early in the technological development of these various approaches to make meaningful comparisons of effectiveness. The area of "MRV" - Measuring, Reporting and Verification - is in its infancy; the methods for measuring effectiveness are still being developed. For some processes it is pretty simple, and for others very complex.

Many of the approaches/solutions in Drawdown involve or are based on carbon sequestration. The book explains how each solution works and gives an estimate of its financial cost to implement and maintain, its overall financial savings, and an estimate of its carbon reduction or sequestration, including a ranking. An essential resource.

https://www.drawdown.org/the-book