Ok - this is the list of stuff that can't be sent to Australia according to the Australian Quarantine & Inspection Service (minus the bits about fresh meat and food perishables which I assume none of us thought of sending)
• seeds including vegetable and flower seeds, unidentified seeds, birdseed and some commercially-packaged seeds
• gifts, ornaments and toys filled with seeds
• pine cones
• raw nuts
• grains and legumes including lentils, popping corn and cereal grains
• raw/green coffee beans
• all plant material including bulbs, whole plants, cuttings, roots, flowers and stems
• soil, including small souvenir or sentimental samples
• gifts, ornaments and toys filled with straw, plant matter, sand or soil
• dried fruit and vegetables containing seeds or fruit peel, citrus and apple peel) and fruit pieces
• remedies and medicines containing herbs, seeds, bark, fungi and dried plant material*
• dried flower arrangements and potpourri
• dried herbs or leaves
• handicrafts—including wreaths and Christmas decorations—containing seeds, raw nuts, corn, pine cones, grapevines, bark, moss, straw or other plant material
• wooden items with bark or signs of insects present
• all mammals, birds, birds’ eggs and nests, fish, snakes, turtles, lizards, scorpions, amphibians, crustaceans and insects
• souvenirs, artefacts and goods made of animal products such as raw hide, feathers, teeth, bones, wool and animal hair
I'll find the list for Canada in a minute