This is the third in a series of tips highlighting features available in Overleaf v2. If you'd like to try v2 for yourself, the beta is now open to the public at https://v2.overleaf.com.
Overleaf v2 lets you search your bibliography to quickly and easily insert the correct citation. As well as simple auto-complete of your bibliography keys, you can choose to search your bibliography entries by author name, title, publisher or year. This will save you time from wading through your .bib files looking for the right keys, or trying to remember them.