Proton Weather is a small, system memory friendly weather app that shows basic weather statistics along with 4 day forecast inside a compact app layout. It can be accessed quickly from Menubar with keyboard hotkey. Both hotkeys for menubar and showing main app window can be customized in the app preference.
CalendarPro is a Google Calendar App for Mac that sends event alerts directly to Notification Center. CalendarPro also lets you access Google Calendar from Menu bar with hotkey which is very convenient to use. This makes using Google Calendar even better than a web browser.