If you look at your user profile you can see:
visited x days, x consecutive
So for the achievement/badge "Fanatic - Visited the site each day for 100 consecutive day" I can calculate the number of days I still need to achieve this.
Is there more API calls one could request to improve achievements/badges?
- How many more up-votes in this tag before silver badge
- How many votes left before hitting the maximum 40 votes in a day
- How many posts have I edited
maybe even more information on how you earned the achievement/badge
There could be a ton more but I hope you get the idea