The whole point of making chocolate bark is the customisation. I mean, who doesn't want a bespoke chocolate bar? As such, you need a recipe that can hold a lot of mix-ins, and this one from Food52 fits the bill. Photo by Meal Makeover Mums.
The link below tells the full tale -- and includes a lot of awesome mix-in suggestions -- but it's a pretty easy process. (You don't even have to temper anything!) Just gather up 1 1/2 cups of (dry) mix-ins, melt some chocolate chunks (not chips) in a (dry) bowl over a pot of simmering water and fold your delicious bits into the melted chocolate. Spread your tasty, chock-ful-of-magic mixture over a large, baking paper-lined area, sprinkle on any seasonings you like (fancy salt, cinnamon and so on) and immediately pop the whole thing into the fridge. Once your bark is hard, break it into shards, transfer to an airtight container and store in the refrigerator until you are ready to consume.