colours that match suit

I've had a bit of a wedding block and struggling to think of colours that would go well with my grooms Navy suit with burgundy tie etc, for the life of me I cannot think what would go with it - he had a tailor made suit and was supposed to pick pastel colours i.e yellow accents but he loved the burgundy which changed the colour scheme totally. I have bridesmaids and groomsmen to think about.

Any thoughts/suggestion would be greatly welcomed and may kick my brain into gear again