An icon will occasionally pop up allowing you to send a Secret Drop to three random Mafia members. Some Secret Drops contain new types of boosts, others contain Reward Points, Skill Points, and the like. Haven't seen Gold Keys in awhile... but still, Secret Drops are like enhanced Mystery Bags-Plus. Unlike Mystery Bags, however, you can only accept a certain number of Secret Drops per day - sort of like the Super Pignatas.
Also from doing jobs, you will occasionally see a 2x Mastery icon pop up, allowing you to send three random Mafia members this boost (and get it for yourself). Then, as you proceed to to jobs, you earn double mastery. These are especially helpful in Gold and Ruby levels in Vegas (or any city's top tier) when jobs are costing a lot of energy and earning 2% or 3% at a time.