So I play on these TTT servers and I recently created my own server. What addons do they use to change the loading screen, gui, and pointshop? By gui, i mean the look of the health bar, remaing time, T/D shop etc.
If you are talking about HUD skins, there are a ton here: http://coderhire.com
Otherwise, Rejax made a good HUD wrapper here: GitHub - rejax/RHUD: Universal HUD wrapper for Garry's Mod
Loading screen: http://forum.facepunch.com/showthread.php?t=1392546