What awesome tools did you discover recently?

Could you share some amazing apps, tools, or services that you have come across recently and thought deserve more spotlight?

Some of my recent discoveries would include:

FontJoy - an online tool for exploring different font combinations.

Neumorphism -an online tool for generating CSS shadows.

VantaJS - animated website backgrounds with a built-in customization.

Share your hidden online gems you just dug out!