Quick Flares

All you have to do is and this has to be during the game (not paused) Press and hold select and then press R1. Lara will automatically take out a flare. You can also throw it too, just press and hold the select button and press R1. This is just a quicker way to take out a flare when you need one fast. 
Submitted by Phillip Mouliatis

Race key and Basement:

Go to the Library. When Lara walks in the doorway, there are two bookcases to the right. Approach the one on the left and press Action. Then, Lara will pull a book and the fire will extinguish, allowing her to climb up the side wall inside the fireplace. After reaching the top, follow the passageways until reaching a room with two levels, with a switch on the top level. Pull the blocks in a way that a hallway leading into the attic is revealed. When Lara pulls the switch, the basement door will temporarily open. Quickly run through the attic, and down to the main hall to reach the basement. Once in the basement, walk through to the second room and look in the tank on the right side. Inside is the key to the race course. To collect it, pull the block in the other room to the center. Climbing up to the hall that leads into the tank
Submitted by codeman10

Lara's museum

Activate the switch behind the diving board in Lara's pool room. Then, go to the door it opens in her main hall. Pull the switch, sprint straight across her lobby and roll into her museum. You'll find cool stuff from her previous adventures... 
Submitted by codeman10

Bonus Level

If you manage to find all of the 59 Secrets in the game, a bonus level called the hallows will be unlocked.
Submitted by MITCHELL CORDELL

Big Guns

Start a new game use all weapons cheat then level select all the way to the globe choose london dropjump of the ledge to kill yourself then choose exit to title screen choose laras house when you start you should have all weapons but no picures of them. you can only have dessert eagle and uzis though.
Submitted by StrangroomJamie

Idle hands Lara

First do the big guns code now instead of picking the Uzis or Dessert Eagle pick the rocket launcher.Lara's hands go crazy! note: after you put this code in you cannot use the action button.
Submitted by Lucas Miller

Energy/Health
This one can be used anywhere in the game..
R2 R2 L2 R2 L2 L2 L2 L2 L2 L2 R2 L2 L2 L2 R2 L2 L2 L2 L2 L2
Submitted by Christie Light

Race Key in Lara's house

This one can be used at Lara's House.
R2 L2 L2 L2 R2 L2 L2 L2 L2 L2 L2 R2 L2 L2 L2 L2 L2 R2 L2 L2 
Submitted by Christie Light

Enter the following during gameplay at anytime, do not pause the game
All weapons 
L2 R2 R2 L2 L2 L2 L2 R2 L2 R2 R2 L2 R2 R2 L2 L2 R2 L2 L2 R2

L:evel skip
L2 R2 L2 L2 R2 L2 R2 L2 R2 L2 L2 L2 L2 R2 L2 R2 R2 R2 R2 L2

All Secrets
L2 L2 L2 L2 L2 R2 L2 L2 L2 R2 L2 R2 L2 L2 R2 L2 L2 R2 L2 L2