This is a colloquial expression, and means more than you expect. We often use it when we're emphasising that what was said before isn't the whole truth. For example; "He was earning a lot of money in his last job, and then some" - His salary was higher than you might expect. "The recent floods devastated our neighbourhood, and then some" - The floods were much worse than you can imagine.

This expression is used in spoken, informal English to suggest that the previous thing you said was an understatement. I can remember only one situation when I have used this phrase. I was talking to a friend about her incredibly sharp, bright and articulate 95-year-old father. I said 'He's got all his wits about him. And then some.' This meant that not only had he not lost any of his faculties, he was actually quicker-witted than most young people.

It means, you have few more things to say, or show