Notable-mentions lists those people who have been claimed by credible sources to possess fortunes to the tunes of multi-millions and billions but claims which have not directly been endorsed by Forbes. These claims are well-referenced and credible. This list is necessary because it is appropriate neither for Wikipedia nor for others to depend on a single-source (Forbes) to estimate the richest people in the world. 

Vladimir Putin
Top billionaires
Notable-mentions (Claims of being less-known billionaires)
Government figures