A little reminder is a phrase that refers to something small or minor, which serves as a gentle and friendly reminder or prompt to do something, such as a note, text message or verbal cue. Full definition
As a former educator, I think kids need to know that their parents are cheering for them to be successful and need little reminders of how they are loved. (therhouse.com)
Sometimes your just need little reminders, little tidbits of food for thought, to help you get through your days, weeks, months, and years as a parent. (theblackbeltmom.com)
This tank's a nice little reminder for next time. (self.com)