Hellboy outside the main series

I just finished reading the main Hellboy series for the first time and I loved it and wanna read more. what other stuff is worth reading? I was looking at the BPRD stuff as well as the Abe sapien solo stuff but I wanna get some recommendations before I buy anything. Also was looking at Mignola’s other books like Baltimore.

The whole universe is great. But I think the next best stepping stone is BPRD Plague of Frogs. That series spins off right after Conqueror Worm and follows the other agents after Hellboy leaves. It takes a little while to get going, but once it does it’s pretty much amazing the whole way through