The best ones are all from native German speaking actors. Movie actors don't need native proficiency since the script is written out for them. The accents are really hard to nail down though and native speakers often have some regional dialect that second language learners almost never pick up.

Mac Steinmeir nails it in Saving Private Ryan and he's Bavarian. Christopher Walz speaks flawless German. His French and Italian sound perfect to me but native speakers consider him "pretty good for a foreigner". He's Austrian.

Christian Slater has a very clear accent in Heathers but he's not supposed to be a native German speaker.