I use Google Now to set reminders quite often. At times when I'd rather not be talking at my phone to add a reminder, I wish I could have a button on my homescreen that would take me straight to the Add Reminder card.
I just found out about the "Set Reminder" option in Google Now's quick settings panel. It's much quicker than typing out "add reminder" in the search bar. But still, having a shortcut to that "add reminder card", or a widget which would add reminders from the homescreen would be pretty advantageous (I would probably prefer a shortcut).
I've tried using a few of the Google Search app's activities, but none seem to take my straight to the add reminder card.