Wish list
Contents
Containers
No one is working on this. It's tough to get started because, despite lots of discussion at various times on this forum, no one seems to really know what they want. Since the containers in question are well-known, it's much more a design problem than an implementation problem.
Update: there has been a lot of progress made towards GC-free containers with EMSI Containers.
Compression/archiving
Opening standard compressed/archived file formats needs to just work. This includes at least zip, gzip, tar and bzip2. Of course, zip already is available and gzip is supported by the zlib module but with a crufty C API. At least gzip and bzip2, which are stream-based as opposed to file-based, should be handled via streams, which means that streams block compression/archiving. Also, since tar and zip are both file based, they should probably be handled by the same API, which might mean deprecating std.zip and rewriting it.
Encryption and hashing
This is more an implementation problem than a design problem. No one is working on it. Some work has been done here but it's unfinished. One of the ideas is to wrap OpenSSL? at first and then implement the most useful crypto primitives in D to avoid library dependency and to make them usable with CTFE.
An improved std.json
Nobody is working on this right now. Wish_list/std.json documents the issues with the current std.json and some requirements for a replacement. Update: See std.data.json for recent development.
An improved std.xml
Maybe Thomas Sowinski is working on a replacement, but haven't seen any updates in a long time. There was also xml2 which was abandoned too.
Matrices and linear algebra
Cristi Cobzarenco's GSoC? project is a good starting point but it needs polish. He has indicated that he wants to get back to working on it but doesn't have time.
Update: Matrices are now merged part of Phobos (std.experimental.ndslice) and Ilya Yaroshenko started a new project - mir which will cover more numeric functionalities.
std.database
This is a large, complicated project because we're trying to define a common API for a variety of RDBMSs. Again, it's more a design problem than an implementation problem. There is at least one current attempt at a unified interface: DDBC
Parallel algorithms
dsimcha has implemented a decent amount of these in his std.parallel_algorithm Github project, but has become somewhat frustrated and unmotivated to finish this project because so many of the relevant algorithms seem memory bandwidth bound and aren't substantially faster when parallelized than when run serially.