We need a trillion more indoor plants.

[Ganoderma]

i dont think they would ever make it into Aus. your best bet would be local, or try to hide a spore print in a package.

many cacti seeds are really easy to grow. some not, most yes. Light helps germination. surface sowing and keeping moist without things that attract mold will increase chaces. Try seeds of these genera, tehy are all very easy to germinate.
Hylocereus,
Cereus
Astrophytum
Lophophora
Echinopsis/Trichocereus
Ariocarpus

for starters