My faves are
Cherry tomatoes (if I am going posh I get yellow nd red ones) buffalo mozzarella and basil (my 8 year old likes making these)
Cut toms in half them load a cocktail stick one 1/2 tomato, leaf of basil wrapped around chunk of cheese, other 1/2 tomato. On a platter drizzled with balsamic vinegar and black pepper. Looks fab, dead easy.
I also get philidelphia and mix it with fresh pesto, or sun dried tomato paste. Buy little brushettas (M&S or whatever) plop a tsp of chesse on a biscuit (sod piping looks too 'done') and if wanted top witha sliver of tomato or whever.
Quails eggs mmmmmm
Good quality tzatiki (TOTAL) mini popadoms, king prawns. Simple assembly job of popadom, tzatzki, prawn. Onto platter, sprinkle with chopped flat leaf parsley and black pepper - this one is a last min jobby and popadoms do go soggy after 30mins
Smoked salmon on brown bread with wedges of lemon
How old are your kids, mine love making 'little' food.
I have a load of red platters (actually christmas 'chargers' meant to go under plates but they were cheap and look great.