Libraries are an important part of any programming language, but you probably already know this. There are many more libraries for D than what you find here, but the ones you'll find here are either complete or usable. For complete lists of different libraries visit DSource.org or AllLibraries.
Probably the first library you should be familiar with is the standard library, Phobos for D1.x or D2.x. If you are using D1.x then you may also want to look into Tango which replaces Phobos. Porting of Tango to D2.x has been started and will work along side Phobos, but nothing official has been released. The second set of libraries to look for is Deimos.
INI parser for the D programming language.
CSV Parser for the D programming language.
- csv.d by Jesse Phillips