There’s maths at work here. Add a tasty something to another tasty something and you’ll likely get a third tasty something! That’s why you may have started to see coffee, chocolate and honey used in beer production - because the flavours work very well together indeed.
Coffee beers are growing in popularity, particularly among American craft brewers. As coffee notes can be found in many stouts and porters already, this is where the lion’s share of coffee beers will exist, and espresso notes can play a starring role. Chocolate is similar story - yummy porters and stouts can have rich, decadent chocolate notes, and as such there are some excellent chocolate stouts and chocolate porters out there. Honey is usually added to beer during the fermentation process, where the sugars are welcome. Masses of sweetness doesn’t always come through in the final brew, but it can add a mellow sugary element and a certain lightness to the body.