Just since March of last year:
The .5500 level caught the 2020 and what’s currently the 18 year low in the currency pair.
The .8000 level currently marks the three-year-high, but even further back that’s the price that helped to elicit resistance in 2017 and 2018, quelling a bullish advance and preluding a reversal
The .7000 level has been big of recent, currently marking the yearly low after helping to set support in September and November of 2020.
The minor level of .7125 is currently setting the 2021 low.
This is just a few, but there’s a plethora of examples here. Psychological levels are great support/resistance levels on a variety of markets, but AUD/USD has been particularly impacted by them as the chart below shows.