I just published on [maxobjects] a set of externals I wrote and which others might also find helpful:
Currently it contains 21 objects in several fields with full Max-like documentation (including Reference docs -- see the readme that comes with the library to figure out how to install that), 3 of them which must be downloaded separately from the Klangpilot page hosted by ZiMT.
Some objects do really basic stuff (like calculation of greatest common divisor or finding closest prime numbers), others are more sophisticated (like the LZO compressor-decompressor or the Chaotic Oscillator).
There is a set of externals designed for binary network communication (TCP & UDP) to be able to talk to any microcontroller with Ethernet port natively from Max. To make binary streaming easier, there is a [buffer~]-like container object in the library that binds a stream of binary data to a Max symbol and lets other objects read and write this named stream. Although currently the streaming objects only support pure binary communication, an upgraded version where all network objects will also understand OSC messages is on the way, as well as a TCP Server & Client object and a multicast external.
All externals are licensed under the Creative Commons Attribution 3.0 Unported License, except the LZO compressor/decompressor, which is a GPLv2 project.
Any comment and bug report is highly appreciated.