I'm an extension developer for MMF2.0/CTF2.5, and I make extensions for fun (originally to learn C++). I still need to clean up this page, but hopefully it has what you're looking for.
All of my extensions are free and open source on GitHub.
Lets you utilize internal, invisible lists that are much faster than the list object. Also allows advanced sorting and more advanced features. A must-have for any list-processing projects!
Allows loading and navigating JSON documents (e.g. to interact with modern web APIs).
Allows advanced control of time simulation in games; makes it easy to rewind time without setting up a complicated array system.
Allows you to define binary file formats with support for recursion and looping. Very useful for utilizing custom file formats.
Requested by Alonso; allows for reading and writing/editing files without loading any part of them into memory.
No Beta Thread | No Release Thread
Not your usual run-of-the-mill function object, this extension allows you to do some advanced things with functions.
Beta Thread | No Release Thread
Allows you to create tree structures with data (named strings and numbers) at each point in the tree.
No Beta Thread | No Release Thread
Requested; allows manipulation of very large integers (integers with 16384 bits, aka 2048 bytes, aka 2 kilobytes). It has not been cleaned or finished.
Allows you to create and modify multiple named 64-bit signed and unsigned integers.
Proof of concept - allows you to emulate fastloops with conditions.
Beta Thread | No Release Thread
Loops events over a series of frames rather than all at once.
Beta Thread | No Release Thread
Allows for creating grouped global values that can be created and set at edit time and run time.
No Beta Thread | No Release Thread
Allows you to get a whole host of information about a volume (drive).
Beta Thread | No Release Thread
Pharanygitis asked me to write the Windows version of his Flash extension since he wasn't very confident with his C++ skills. I don't remember what happened after that; it was back in 2012.
No Beta Thread | Release Thread
Originally written by Jaffob, it was requested that this be ported to Java. Allows you to open any URL of any kind that the JVM can understand, such as web addresses, local file addresses, network addresses, etc.
No Beta Thread | No Release Thread
Originally written by Ouly.
No Beta Thread | No Release Thread
Originally written by Jaffob.
Beta Thread | No Release Thread
Testing to see if I could have an arbitrary number of properties. I limited it only to 26 because they all had to have names and I just used an array from A to Z, but this shows that in concept properties are very dynamic. This eventually led to the Advanced Global Values object.
Beta Thread | No Release Thread
A base extension made for Dines to help him with how to do his properties idea.
No Beta Thread | No Release Thread
Made for Jacob as an example. I don't think he ever got around to doing what he intended to to with it, but it led to me making the Timeline object.
I've made a help file for James' Lacewing extension set. Here is Revision 2, as well as the thread for it.