Well for myBB I use the highly popular forum cash plugin - NewPoints. It is what most users of myBB will tend to use as there are some great mini-plugins for it that allow you to expand its functions such as a lottery function and even a shop feature. It is a great plugin as it helps reward the forum users will points that if the forum admins allow can be either exchanged for virtual items or even real life gifts
Don't have any, and won't have any. I simply don't see the point in my niche for the functionality, and feel that it would just add unnecessary workload for a very little vanity for few users. I think I'm better off by not bothering with one in the first place, and instead focusing on the actually meaningful content that's needed and asked for.
But if there was many requests for such, I might have to reconsider.