Top 100 list

[cornelius]

Has anyone been able to code a top 100 list for maybe highest volumes,
most actives, etc... Would something like that be possible?

[NinjaTrader_JoshP]

You are looking for a market scanner of sorts which is not available in NinjaTrader. Indicators are not multi-instrument at this point in time, but will be available in NT7. You could try using a strategy to create your list, but in either case you would need to add thousands of instruments to the NinjaScript for it to work.