When looking for a particular plugin I often get a lot of suggestions, a lot of plugins. But many of them are so old they only work for versions beneath 3.0, and today I even encountered one that was compatible up to version 1.0 ;)
It would be a good idea imho to clean of the database, removing all plugins that are not compatible with at least 3.0 and which at the same time are not updated for some time (= years). Or move these plugins to a different category 'Deprecated plugins'.