Crommelin concrete sealer at a perfectly cromulent price.
Spotted at Bunnings Altona. It's a yellow clearance sticker, but I could not find the product on their website so you might have luck at other stores as a deleted product being cleared out.
OK I don't know how this stuff stacks up against other products. But even though it's marketed towards freshly poured slabs, it does say it can work for existing concrete. And at the moment pretty sure my garage/workshop has nothing.
And way cheaper than anything else on the Bunnings site for 10L. Aldi are selling 5L "patio sealer" for $30.