I agree eucalypts are unusual, I also find them beautiful, especially ones with smooth light bark like Ghost Gum and Citriodora, which has light pinky-orange bark! Such a presence!). I've never seen a Rainbow Gum but would love to one day!

I live in South Australia and I was surprised to hear about all Eucalypts having 'leaf dimorphism' (that is what I searched for, then learned that it's usually known as 'heteroblasty') I have of course seen it many times in-the-wild, but it is not universal to all Eucalypts.

Banksia, Grevillea and Hakea are also very beautiful Australian native trees/shrubs imo, but they are a different group: Proteaceae. And there's a fascinating fruiting small tree called 'Quandong' that's in the Sandalwood family (still seems bit related to eucalypts or maybe Wattle (Acacia) when looking at it in real life though).