No certain units you should take. To transfer, you need to keep your uni marks up (for commerce at usyd/unsw I’d say at least distinctions and for MQ at least credits). It usually doesn’t matter what units you do, as long as you’ve gotten good marks in uni.
However, you might want to take certain units that will give you credit for your new degree. Usually these are the really first year generic units like accounting 1A/1B, macroeconomics, microeconomics, but sometimes it is hard to get degree credit as different unis have specific requirements