Just wanted to remade one of the stickies as it is outdated (last post in 2k5) and many of the links are dead.
Matrix1Utils -
http://forum.thegamecreators.com/?m=forum_view&t=85209&b=18
Great, all-around plugin. Adds functions for handling INIs and key->value pairs (although it seems only for strings), networking for both TCP/IP and UDP protocols, 3D Math function, timers and more!
Enhanced Audio Plugin -
http://forum.thegamecreators.com/?m=forum_view&t=74019&b=5
Adds support for following formats: Ogg Vorbis, FLAC, AIFF, MOD, S3M, XM, IT in addition to what is already supported by DBP (mid, mp3 & wav)
D3DFunc.dll -
http://www.dbdepot.co.uk/d3dfunc.html
Improves speed of rendering text by using directly DirectX for that.
Barnski Lua Plugin -
https://forumfiles.thegamecreators.com/download/2407013 (direct download)
Plugin that adds support Lua scripting language to your games for scripting.
Sparky's collision plugin -
http://forum.thegamecreators.com/?m=forum_view&t=31051&b=5
Great collision plugin that helps out a lot when making 3d games in general. After all, every 3d game needs collisions.
Winch's plugins -
http://winch.pinkbile.com/wiki/index.php/Main/Plugins
OPEN to APPEND adds support for opening files so you can add things on the end of the file
Message Box adds support for using standard message boxes (syntax quite similar to VB's MsgBox command). Also there are quite few useful tools there.
DKShop -
http://forum.thegamecreators.com/?m=forum_view&t=39906&b=5
Adds many functions regarding 3d math. Made by Dmitry
Nuclear Glory -
http://www.thegamecreators.com/?m=view_product&id=2085
A collision plugin from TGC.
Unity -
http://www.thegamecreators.com/?m=view_product&id=2081
Scripting plugin using Lua language from TGC.
STYX -
http://www.thegamecreators.com/?m=view_product&id=2079
General use plugin from TGC.
Something I've miss? If so, please post, I will update it.