[thrash]

Second the Conan recommendation. Additionally, for atmosphere (more than point-by-point similarity):

Dragonslayer (1981)

Time Bandits (1981)

Willow (1988)

There's an entire genre of Japanese anime inspired by D&D by way of console video games:

Record of Lodoss War (1990) was explicitly based on Ryo Mizuno's fantasy RPG campaign. Rune Soldier (2001) is a more recent comedy series set in the same universe.

.hack//Sign (2002) is very moody and atmospheric, with first rate background music.

Sword Art Online (2012) is very flashy, with excellent graphics.

Log Horizon (2013) is also excellent, with a more scenarios.

Konosuba (2016) is a straight-up parody of standard D&D-derived video game tropes. The problem is you may lose players to watching it -- it's that funny.

Note that I watch all these in Japanese with English subtitles, so I can't say whether the English dub versions are any good or not.