Games will be abstract strategy gamesYou're running an elective. I run a "club".
For the past 3 years I have had middle-schoolers in an after-school program one day a week, 1 or 2 hour sessions, for strategy games. That can include abstracts but is not exclusive.
My purpose is to allow a luck element but not let it dominate (I tell them that is why Monopoly isn't in the program). The games are really problem solving but I don't mention that. They don't feel "taught" but they are definitely learning.
As a rule, I do not use card games. Coloretto is an exception.
Blokus certainly belongs on your list.
Manhattan is the strongest, fastest demonstraton of why/how the games I show are different from what they already know.
...but do not really want to bring them all into a classroom. They will get really beat up, thats just what happens at school with kids.Sigh ..