Halo Combat Evolved
HMT version 3.5 is a great program (More like a tool) to mod Halo Trial or PC with.
HMT lets you mod and edit Halo 1 pc. It lets you make weapons infinite ammo, do pmi and much more. Since this has plugins, it lets you do much more than normal hmt does.
Halo PC Modding Tool Belt is a compilation of tools and tutorials to mod Halo PC.
6 formats for widespread use (.txt, .utf, .htm, .doc, .rtf, and .xml) and contains shed loads of info about how to mod Halo PC.
A 30 day trial for ms3d. This is a modeler program that lets you create and edit models for halo.
HHT is a program that lets you edit and mod halo 1 pc. This version has plugins that let you edit more tags in more ways. (best for moderate-advanced modders)
This is a Halo Modification Kit. It lets you run hht, hmt, and sparkedit. All of these are used to mod Halo 1.
Halo 2 and Halo CE modding tool.
Version 4.0 of Jackle's Modding guide is now up! This version features six formats for widespread use (including .txt, .utf, .htm, .doc, .rtf, and .xml) as well as a number of additions to the guide.
All the halo trial modding tools you need, including...
An installer for My Modding Kit. It includes Halo PC modding programs, camera hacks, developer hacks, tutorials and several precreated mods by me. Note: Don't use rar unless this doesn't work.
Plugins for extra commands and weapons choices accesories and other tools for Halo Modding Tools v3.5
The best of all Halo map modding type programs in my opinion... Has the most options and features within it unlike HHT v5
Has all your Halo PC Modding Programs - HMT v3.5, HHT v5, Sparkedit and much, much, more