A whipped cream topping could work well - add a little sugar and some extract for flavour.
For loaf like cakes or muffins (lemon bread, for example) I don't ice them, but immediately after taking them out of the oven I drizzle with a mixture of fruit juice and sugar which soaks into the top and gives a bit of sweet crunch when dried.
For coffee cakes, I use a mix of flour, butter and brown sugar, maybe with a bit of cinnamon, sprinkled over the top in a thick layer before baking. This makes a crunchy, rich, not as sweet as icing topping.
You could vary the ganaches - add liqueurs, make white chocolate ganache with fruit flavouring, etc.