I use this odd one out activity with my Year 12 and 13 students (UK system) to check their knowledge of whether nouns are masculine or feminine based on their endings. This includes both regular nouns which follow patterns such as feminine nouns usually ending -tion and irregular nouns.
The first slide has 7 groups of 4 nouns from which the students have to identify the odd one out. Beyond the grammatical rules I also invite the students to think outside the box and come up with alternative answers!
obstacle chômage combinaison fardeau
combinaison = fem
tension fonction philosophie collège
collège = masc
problème réflexion mystère rejet
réflexion = fem