Is there a complete mimic location guide?

I really want the mimic helmet to help with farming, but I've not had the luck of dropping one yet. I read that if you kill them all you're guaranteed the drop but I've finished the game now and it hasn't dropped so I must have missed one.

I found this guide but it's incomplete and I'm fairly certain I have all the ones listed. http://www.gosunoob.com/dark-souls-3/mimic-chest-locations/