>>82310601Starman has some pretty fucking deep cuts in terms of DCU continuity, but it does a great job of explaining that shit in context, so it's not necessary.
>any other crossoversJack was in the first few issues of the modern JSA revival when Robinson was writing it, but he leaves the team, hands over the cosmic staff to Courtney/Stargirl, and retires when Johns/Goyer takes it over.
There's also a Starman/Batman/Hellboy crossover written by Robinson and Mignola and it's pretty fucking great.