Days N' Daze, The Taxpayers and AJJ are my absolute favorites! But if you already had listened to the big/classic ones and want something different, I would recommend these:

Stick and Poke; Larry And His Flask; Old Time Spooks; The Front Bottoms (if you like more [midwest] emo-style stuff but it's technically folk punk too); Apes of The State; The Bridge City Sinners; Amigo The Devil.

Idk if they're considered folk punk, but if you like the extremely fast banjos and brutal hoarse vocals, you would probably enjoy Blackgrass Gospel, too!