I use...

I use Investing.com

https://au.investing.com/indices/us-spx-500-futures-streaming-chart

Just google 'Investing.com' with 'ASX200 futures'
and also 'SP500 futures'

By default we'd be referencing either of those.

The Dow30 is actually referred to more out of tradition, being quite limited. And of course the Nasdaq is mostly tech & pharma.