What is Garry's Mod without addons? Well, it is still an amazing sandbox game, but you miss out a lot. Addons usually need to be installed in the addons folder in \Steam\SteamApps\common\GarrysMod\garrysmod\.
While only few addons are installed like this, many of those addons have to be (more or less) constantly kept up to date via github or subversion (SVN). To facilitate this, you can use a program like TortoiseSVN. Once installed, you can create a folder named after your desired addon in the earlier mentioned addon folder. Execute a right click on that folder, select SVN Checkout and enter the corresponding SVN link. The most important SVN links are listed in a table below.
Ever since the GMod 13 update, most addons are now installed with the steam workshop. This is easy for the players and also for the server hosts. Addons on the workshop will automatically be kept up to date on both server and client.
| Addon Name | Description | Link |
| Armored Combat Framework (ACF) | Adds weaponry with simulated ballistics, a damage system, engines, differentials and transmissions. | https://github.com/nrlulz/ACF.git/trunk |
| Advanced Duplicator 2 | Duplicates contraptions and saves them to your hard disk, supports old Advanced Duplicator files. | http://advdupe2.googlecode.com/svn/trunk/AdvDupe2 |
| Generic Default Combat Weapons (GDCW) | A set of weapons with nice models and realistic bullet physics. | http://generic-defaults-combat.googlecode.com/svn/gdcw |
| Holopad | An ingame tool to do hologram modeling, which can be compiled to expression 2 files. | http://holopad.googlecode.com/svn/trunk |
| TDM Carpack | A large set of highly detailed cars from various brands. | http://svn.code.sf.net/p/tdmcarssvn/code/trunk/ |
| Wiremod | The essential addon to make proper I/O systems and many other linkages, where you normally had to use your numpad. | https://github.com/wiremod/wire/trunk |
| Unofficial Wiremod SVN | Wiremod tools, which are not supported anymore, but useful anyways. | https://github.com/wiremod/wire-extras/trunk |
| ULX | The oldest lua-based administration mod. | https://github.com/Nayruden/Ulysses.git/trunk/ulx |
| ULib | The base addon, which ULX needs. | https://github.com/Nayruden/Ulysses.git/trunk/ulib |
| Constraint Core | This is an expression 2 extension, which allows you to create constraints. | https://github.com/PTugaSantos/Wire_Expression2_Constraint_Core |
| Addon Name | Description |
|
Advanced
Duplicator |
Duplicates contraptions and saves them on your hard disk or on the server; this tool is the original wiremod duplicator tool. |
|
Buoyancy Tool |
Allows non-wooden props to be able to float, useful for boats. |
|
Climb SWEP 2 |
Allows you to do parcours like jumping (first person only), including wallruns, grabbing ledges, etc. |
|
ColorMater Tool |
A tool to apply/copy colour and material from/to one prop at the same time. |
|
Easy Bodygroup Tool |
Some props are able to use different skins or body groups; this tool lets you change them with a simple right-click. |
|
Fin 2 |
The fin tool allows you to use the dynamics of props to let them be affected by their speed and their resistance angle; this is useful for spoilers, boat rudders, plane wings or even propellers. |
|
Make Spherical |
Allows you to make any prop a lua-coded sphere; useful for wheels, which would, under normal GMod physics laws, jump or sink into the ground. |
|
Model Property |
Allows you to change the model of a prop whilst maintaining the colour, material and angles. |
|
Multi-Parent / Unparent Tool |
Allows you to (almost) laglessly attach props to another; parented props don't react to the world or other props. |
|
No Collide All Multi |
Can disable collisions with other physics props for many props at once. |
|
PHX props missing materials |
The PHX model pack has not alway been integrated in the regular Gmod, but when Garry implemented it, he didn't import all textures properly; this addon fixes any texture errors. |
|
Physics
Constraint |
This is useful, when you want to build something, which should tear apart realistically; the tool automatically creates force-welds to the adjacent props. |
|
Re-Located
STools |
Restores important and useful tools of the previous GMod version. |
|
SmartSnap |
Adds a grid to which you can snap to with your toolgun while building; useful for accurate building. |
|
SProps
Workshop Edition |
The essential and optimised prop pack for every GMod builder. |
|
Stacker
STool |
Allows you to easily stack multiple props onto or next to eachother. |
|
The sit
anywhere script! |
Allows you to sit on anything, whether it's moving or not. |
|
Visual
Clip |
Can visually clip props so that you will only see the unclipped part of it. |
|
Weight
STool |
Can set a custom weight to a prop and most entities. |
|
White Texture
Pack |
A pack of realistic clean textures, useful for building. |
|
Wiremod |
The essential addon to make proper I/O systems and many other linkages, where you normally had to use your numpad.
Warning: This addon also exists as SVN download. Usually the SVN version is the newer version out there. |
|
[Official]
Precision Tool |
Allows you to accurately place constraints, works best in use with SmartSnap. |
| Addon Name | Description | Link |
| Axis / Ballsocket Centre | Allows you to simply create Axis and Ballsocket constraints to the center of props, very useful if you want a prop to spin above/below another prop. | https://dl.dropbox.com/u/7934790/gmod/stool_axisbscentre.zip |
| Physgun Buildmode | Useful if you only use a touchpad mouse, but also for regular players; this allows you to carefully move props with the physgun whilst keeping their orientation and such. | https://dl.dropbox.com/u/7934790/gmod/physgun_buildmode.zip |
|
PHX Spawnlists |
Garry didn't implement the original PHX spawnlists, when he added PHX to the official game; this is a rough fix (one list is still missing) | http://1drv.ms/1eOx95N |
| Precision Alignment | The non+ultra addon for accurately placing constraints. | https://dl.dropbox.com/u/7934790/gmod/stool_precisionalign.zip |
|
Wheel2 |
The predecessor of Make Spherical, do not use this unless you want it to try out old duplications that still use Wheel2. | http://1drv.ms/1eOxG7D |