Not all perfect examples (e.g., some aren't metal, but they all have their own edge to them)... Kittie, Lamb of God, Dream Theater, Green Jelly, Heart, Ministry.

(Well, as you probably know "nirvana" is not exactly a perspective that many ordinary people welcome, and it is in fact very far from some concepts of "heaven"; "Nirvana" for the eponymous band meant "induced bliss"; the band was far from fixated as e.g. Cobain found documented inspiration in the Damned ("Come as You Are" is apparently a citation of "Life Goes On") and the latter just lightly enjoyed the eerie spirit uncommittedly - a spinoff was Captain Sensible solo projects with "Wot"...

Now back to the topic.)

Brainstorming...

Greenland not being that green.

Flaming Saddles and all the names of restaurants serving some kind of spicy food, whose names emphasize the side effects.