crimson charms?

cocroaches are located north of stronghold security and south of edgeville. below the 2 yew trees in a "rift". I think you have to start a miniquest or something to go in that way, though.

They give pretty decent charms, mostly crimson but all charms drop.
I think black demons are better and waterfiends definately better but cockroaches are easier to access.

 

Use cannons at black demons. They drop plenty of charms, and effigies. Save the effigies until higher levels when they'll be worth more exp.

 

Waterfiends are the best imo for crimson charms although Greater Demons drop a fair amount to say they are a lower level.

 

I personally bot SW for my charms.

It may take longer depending on what monster you do but you don't have to worry as much about getting banned.