Simple Green (as linked by @TonyLPowell above) . In the US, you can buy it at any big box store in gallon size, and then dilute it (or not) as desired. He linked the unscented one, I’ve only used the regular one, but basically the same deal.
I dilute 1:1 with water for cleaning drive my drive train. I dilute 20:1 for cleaning basically anything else. Best part? Easy, “green” disposal.
I soaked my greasy cassette and chainrings in 1:1 simple green, then wiped it down, clean as a whistle.