There is a Wiki page for the Indy car series.
wiki.radioreference.com
There is some basic information on the Indy Car Series webpage.
The Official Site of IndyCar News, Drivers, Schedule & Shop | IndyCar.com
www.indycar.com
It states that for driver frequencies, first find the specific race:
Full 2025 NTT INDYCAR SERIES race schedule, ticket information, race results, race dates, race times, and track information.
www.indycar.com
On the page for a specific race, select the Spotter Guide.
Everything you need to know about the 108th Running of the Indianapolis 500 presented by Gainbridge. Find race, driver, track and team information, as well as news and results.
www.indycar.com
That will take you to a page with drivers and their specfiic frequencies.
Everything you need to know about the 108th Running of the Indianapolis 500 presented by Gainbridge. Find race, driver, track and team information, as well as news and results.
www.indycar.com
Also see this page, which I found using a basic Google search.
NASCAR & INDYCAR & INDY NXT Scanner Frequency Lists. Rental Scanners at Indianapolis Motor Speedway. Buying and Choosing a Scanner.
www.indymotorspeedway.com
If you are using ProScan, you should be able to copy the list of driver frequencies to the Windows clipboard, then ProScan will let you specify which column (on the clipboard) goes to what field when programming. (I don't have the ARC software, but you might be able to do someting similar with it.