Go for a walk/run (Outside in nature if possible!)
Ride a bike
Clean and Organize any room in your house or your car
Take a long bath or shower
Write a list of all the things in your life that you are grateful for.
Talk to someone. Try talking to someone who will just listen to your issues and not necessarily try to fix them.
Go on a date. You can even take yourself on a date if your significant other is busy.
Write in your journal. Nothing feels better than seeing your thoughts on paper and getting it all out.
Read a book
Draw or take pictures.
Color. I love my adult coloring book to clear my mind.
Turn off your phone, computer, and television. Relax screen-free.
Start your own DIY project that you have had saved on Pinterest forever.