Comparatives and Superlatives feature in a lot of books and courses. They aren't massively difficult to teach, or indeed learn. But, as with everything in the English language, practice makes perfect!
And, as you should all know by now, what better way to practice than a board game (rhetorical question, there is no better way)?
Biggest, Smallest, Fastest, Tallest looks a little daunting at first. It is full of words of varying lengths, with little space in-between. Each square has an adjective, a comparative and a superlative (all from the same, base word) e.g. Big, Bigger, Biggest. The student that lands on the square must then name 3 things (animal, vegetable or mineral as it were) that fit that set. So, a horse is big, a house is bigger and a city is the biggest. There are 52 squares in all, each with a different adjective, comparative, superlative set. So there may well be more words on their than you have taught your students and made need to help them with a few of the answers.
It is, of course, photocopiable so you can easily create as many as you need for a class. I would suggest having 3-4 students play with each board.