Search in cozy calendar coud be a powerfull tool ! not so hard to add (filter + list).
For example, each month (week, year, randomly), you can search for a specific word and get the complete list of events in which this word occurs.
Very usefull for many purpose, calculate time you spend for an activity (associate with this specific word), billing customers...
Another great add coud be calculate (sum) time of events (filtered by a search) betwen two specific days; so you coud easily know how much time you where cooking in the kitchen between 12 december 2016 and 31 december 2016 (if you add the word "cooking" in your events, and filter with these days...)