You have two options. New old stock on fleabag or somewhere on the web.
Go to Holley.com and under brands look up Accel and see if they have anything. If not, look under Mallory and see what they have.
I didn’t look real close but if you have a vacuum advance distributor it can be more problematic to find a rotor.
I know the Mallory VA distributor rotor with a Unilite is impossible. I made up a spacer to raise the module so you can use a non VA rotor on a VA distribution.
Of course that’s with a Mallory distributor. I’d have to see different pictures of yours to see if it would work.