There are several options available for formative assessment that are currently being used in the district with our students. Most of the focus tends to be on Google Forms Quizzes, Socrative, Kahoot!, and Quizizz.
Whichever formative assessment tool you choose to work with, be sure to:
focus on the learning
limit to 5-10 questions
consider giving options to retry
consider fill-in-the blank (one word or number, if math)