GAME-BASED LEARNING PLATFORMS (Gamification)
I only have listed game-based learning platforms I use in class. I am sure there are other great ones out there.

Kahoot:
Log in - Kahoot!
Kahoot is like a teacher led multiple-choice trivia game where you select a topic to review. Students get more points for choosing the correct answer the quickest.

Quizziz:
Quizizz — The world’s most engaging learning platform
Quizziz is like kahoot, but it has an option to be teacher led or an option to let students advance through the questions on their own. The student who gets the most questions correct the quickest gets wins the most points.

Blooket:
Play Blooket
Blooket is like Quizziz in the way they can go through the questions on their own pace, but their correct answers help them in whichever game mode it is the teacher sets. Different games modes have students either racing down a track, working in a factory, working in a cafeteria, et cetera.

Pear Deck's Flashcard Factory:
Flashcard Factory — Pear Deck
The students in essence play "Pictionary" with whichever vocabulary word they receive, and the pictures (along with definitions written for them) are then reviewed by the teacher and given a green stamp for good or a red stamp for bad.

GIMKIT (30 Day Free Trial)
Gimkit - two engaging tools in one
This is like Blooket; however; it has game themes that seem to be more geared to upper grades. In my opinion like 5th, 6th, and Jr & Sr High School. For example, they have an "AMONG US" and "ZOMBIES vs HUMANS" themed games.