You can find tons of english versions of mangas in any bookstore, and even local libraries! As for the anime, there are dubbed versions, even the more obscure ones.
One of my favorites, which is pretty adult in its violence, is Berserk. You can find it online for free. Its set in a medieval-esque setting and centers around the lead character Guts and his adventures with a mercenary band. It gets fantasy elements eventually.
Bleach is pretty popular and marketed mainly to young adults.
There's a series called Hellsing that centers around Dracula/Alucard as he's known in the show, acting as an agent for a special anti-supernatural organization based in Britain. Expect supernatural action and tons of blood.
Cowboy Bebop is a classic, and nowhere near as violent or bloody as the ones mentioned before. It has a tight story and delivery that calls back to jazz in many thematic elements, and is set in a space-faring future. Samurai Champloo is a similar anime made by the same company but is a bit more violent, with hip hop overtones set in the downturn of the samurai era of Japan.
Dragon Ball (and Z, and GT) are also classic!
Black Lagoon centers around modern day mercenaries operating out of South Africa taking jobs with various sorts of objectives that take them across the world.
All the ones that I mentioned are high in violence/adult themes, and there are tons more I could mention but aren't too sure what you're looking for other than 'not kid stuff'.
Hope I helped!