ECB2's Natives
set_vehicle_engine_on = 0x82E2FD68
set_vehicle_dirt_level = 0x82E2FBC0 
SET_PED_INTO_VEHICLE= 122686585 
SET_VEHICLE_NUMBER_PLATE_TEXT= 1074763094
SET_VEHICLE_COLOURS= 1475494483
SET_LOCAL_PLAYER_INVISIBLE_LOCALLY= 1984913954
SET_PLAYER_MODEL= 2001357908
SET_VEHICLE_ENGINE_ON= 2143061745
SET_PLAYER_INVINCIBLE= 3753484962
SET_VEHICLE_FIXED= 390503073
SET_PLAYER_WANTED_LEVEL= 3080753483
GIVE_DELAYED_WEAPON_TO_PED= 1483264525
REMOVE_WEAPON_FROM_PED= 2620912160


THESE ARE FOR ADDING TO HIS MENU (TEST NATIVES)
TASK_HANDS_UP= 2378963397 -------- WORKS (BEST )
SET_VEHICLE_DOORS_LOCKED_FOR_ALL_PLAYERS= 2300291236 --------- BAD only works for yourself...
SET_GROUP_FORMATION= 150652729
SET_POLICE_IGNORE_PLAYER= 3873337783
TASK_COWER= 2633089435 ------------------------------ WORKS
TASK_SHOCKING_EVENT_REACT= 2614102735 ---- BA(
TASK_WRITHE= 266097916 ---- BAD 
TASK_TURN_PED_TO_FACE_ENTITY= 1010288487
TASK_GO_TO_COORD_AND_AIM_AT_HATED_ENTITIES_NEAR_CO ORD= 1066481038 ------ WORKS BUT MYSTERY
TASK_PERFORM_SEQUENCE= 1302314257
TASK_SYNCHRONIZED_SCENE= 1327595131
TASK_PLAY_ANIM= 1521832646 ----------------------------BAD 
TASK_SCRIPTED_ANIMATION= 4230860615
TASK_TOGGLE_DUCK= 1641004223
TASK_WARP_PED_INTO_VEHICLE= 1708434269
TASK_STAND_STILL=1870698077
TASK_LEAVE_VEHICLE=2064728518 ----------- BAD
TASK_REACT_AND_FLEE_PED= 2321755096
TASK_SHOOT_AT_ENTITY= 2886087113
TASK_SMART_FLEE_COORD= 3001452284
TASK_ENTER_VEHICLE= 3093863246
TASK_PATROL= 3106822902
TASK_ARREST_PED= 3155105085 -------------------BAD 
TASK_AIM_GUN_AT_ENTITY= 3190993846
TASK_VEHICLE_DRIVE_WANDER= 921439920

 Originally Posted by reddinos 
TASK_HANDS_UP = WORKS/Players can't move.
TASK_WANDER_STANDARD = WORKS/Players walk forever.
TASK_COWER = WORKS/Players can't move(cower).
TASK_PATROL= BAD/fREEZE
TASK_CLIMB = WORKS/Players can't move.
TASK_COMBAT_PED= BAD/Does nothing.
SET_PED_IS_DRUNK= BAD/Does nothing.
TASK_JUMP=WORKS, but only for you.
Tutorial:
1.) Go here [ PS3 - [All GTA V HASHES+Natives Codes List | Se7enSins Gaming Community ] , click on hashes or natives doesnt really matter. 
2.) Once you have your offset or hash, open UPDATE.RPF with libertyv, then go to script.rpf and export it to your desktop.
3.) Extract MODMENU.CSC from script.rpf onto your desktop, OPEN IT WITH HXD(HEXEDITOR).
4.) Click on SEARCH, FIND, if you have a HASH use Integer Number and change little endian to BIG ENDIAN (WOAHHH LOL). ( I am not 100% sure if Im correct or not, I believe you use datatype HEX-VALUES if your using offsets.)
5.) Use one of the above natives, your gonna want to copy the number not the words. SEARCH, FIND, paste the hash into the search box. SEARCH.
6.) If correctly found, you will see the OFFSET highlighted. 
7.) SEARCH, REPLACE. CLICK ALL for search direction. And enter the native hash you want to replace into the second box. And hit replace. 
8.) Click save. 
9.) Reimport into Script.RPF then save. And import the script.RPF into your update.rpf and save your UPDATE.RPF. And replace your UPDATE.RPF. 
10.) GO TEST NOW! 
11.) Enjoy!

To change the models in ECB2's Menu:
This is iffy, I haven't tested it myself, but this is only for people who want to test it out.

You can pick a Model that u want to change - here is a list 

U_F_Y_corpse_01 = 2624589981,0x9C70109D 
S_M_M_SnowCop_01 = 451459928,0x1AE8BB58 
U_M_Y_ImpoRage = 880829941,0x348065F5
S_M_M_MovAlien_01 = 1684083350,0x64611296
U_M_Y_Zombie_01 = 2890614022,0xAC4B4506
IG_MrsPhillips = 946007720,0x3862EEA8
IG_Hunter = 3457361118,0xCE1324DE

So lets say you want to replace the Corpse U_F_Y_corpse_01 = 2624589981,0x9C70109D 
with A_F_Y_Topless_01 = 2633130371,0x9CF26183

You open ECB2 modmenu.csc in a hex editor then you search for 9C70109D (Corpse) and replace it with this 9CF26183 (topless) it always starts after 0x the rest u have to copy ....

So after you searched and replaced it , now u can save it and test it 


Check out KryptusX's tutorial on how to change fonts and colors on your edited menu:
[SOURCE] VCAHax 1.0 Modified Colors/Fonts [TEMPLATES]

List of All Game Fonts:

Chalet London Nineteen Sixty
Sign Painter House Script 
Rockstar TAG
GTAV LeaderBoard
Chalet Comprime Cologne Sixty
Chalet London Nineteen Sixty Numb
Pricedown GTAV Int
Handstyle Heist
Helvetica Neue LT 47 LightCn
Helvetica Neue LT 67 MdCn
Helvetica Neue LT W1G 55 Roman
Times New Roman CE
Courier Twelve MT Std
GTAV Taxi Digital
GTAV Courier
Chalet Comprime Cologne Sixty

Credit for list: ErOoTiiK


 Originally Posted by ErOoTiiK 
there are two values ​​for each SET_TEXT_SCALE one for the width and one for the height
so, for the first SET_TEXT_SCALE go to 12A in HxD for the first value you have "3E CC CC CD" = 0,4 in xsc toolbox, and for the second value go to 12F you have "3E CC CC CD" = 0,4 in xsc toolbox

for change use Floating Point to Hex Converter 

in float value type for example 1 and click on convert to hex, now just change "3E CC CC CD" for the new hex value
for the second text scale : 1DD 1E2

Credits:
ECB2 [Modmenu]
ResistTheEarth [Helping me to understand how to change natives, "sort of" lol .]
TheSaltCracka [Helping me test and find natives]
KryptusX [Fonts]
ErOoTiiK [HELPFUL QUOTES]
and someones post I got the model tutorial from a while back.