I have a couple steel spikes and have been looking for monster blocks, and I checked out the v2 update and it said that there was another block they spawn from. Does anyone know if so that would help a ton. Thanks and have a great day!
A super easy way I found is to look for hills areas and look for exposed coal ores above ground. Mine all them and you should get some to spawn. You can also do this below ground but you'll have a lot less space to work with.