What checkmates are appropriate for 7 year old kids? I give chess lessons to children and I've been told by my boss that the most important ability at this age is the capacity of delivering checkmate to the opponent.

I've taught them the back rank mate, the smothered mate, pillsbury's mate, mate with a rook, ... Among many others.

I was wondering what checkmate patterns would also be appropriate for children this age. I know that, for example, it would be too difficult for them to learn the 2 bishops checkmate.

P.S. The children are not going to engage in any kind of competition, the most important objective of the class is that they have fun.
The approach I use (also with older kids) is that the process of mating involves putting the king in jail and making the walls smaller and smaller ...

For something like smothered mate it is the pieces on the king's own side which build the walls! But when there is not much material left on the board you have to build the walls with your pieces. You can then show them the kind of walls the queen, one rook and then two rooks make. I would also show the wall that one king makes for the other, even though this is only 3 squares long. It comes in handy for KRvK. Of course every wall (apart from the queen wall because the king can't approach the queen) has at least one hole in it where the piece stands.

Once you have this principle established it is easier to teach them the KQvK, KRRvK, KRvK endgame mates. With the ideas behind the "build a prison wall and make it smaller" I believe you can even introduce the KBBvK endgame to young kids although they likely won't succeed most of the time. However it introduces some more interesting ways of handling the two bishops which may help them in the middlegame and I think is still well worth while.