Empathy and Social Awareness Curriculum
This curriculum from Teachers Pay Teachers, geared towards K-2, includes many well done SEL components for use in the classroom. I liked the Empathy Game included, Someone Else's Shoes, and a Wrinkled Heart. Any of these ideas would make quick #SELHacks in the classroom!
The Wrinkled Heart, for example, involves having the child make a heart that represents their heart. You can embellish this activity by having them write things that matter deeply to their own personal heart. Ask them to wrinkle their paper, and then try to smooth it out again. Discuss what happens in our hearts and theirs when we hurt someone's feelings.
In the Empathy Game, you practice having kids talk through different scenarios in which they can practice showing empathy to others.