best mods to be a thief with

[UnderDog]

I havein't really seen alot

[Trigger]

if your playing race without nighteye you might like this mod " Aura Whisper with nighteye " and also " Assassin Poisons "

[Ilja]

You have a private profile, so I don't know how much experience you have in the game. Here are my favorites.

Thieves Guild Requirements - No Auto Quest Start Brynjolf by kryptopyr
Bryn is now a bit better judge of character. You will actually have to play as a thief before getting invitied to the guild.
http://www.nexusmods.com/skyrim/mods/14157/?

Improved sneak detection by Dragonborn77
Makes some changes to sneak mechanics. Works well with the third mod in this list and I recommend using them together.
http://www.nexusmods.com/skyrim/mods/23353/?

Immersive NPC in the dark by hacknpaint
The previous mod made changes to how NPCs detect you in the light. With this they are actually required to carry lights themselves. While this would otherwise made them easier to pick, the sneaking at night and dark indoors gets not actually much better balanced.
http://www.nexusmods.com/skyrim/mods/52239/?

Trade and Barter by kryptopyr
Not directly a thief mod itself, but overhauls the trade so that your position actually matters. This will affect to your position in the guild as well, when you are buying or selling stuff. This makes the progress in the game world actually mean something - at least for those dealing with black market wares. Very good mod and one of my essentials.
http://www.nexusmods.com/skyrim/mods/34612/?

These mods will boost your experience as thief. I am using them with SkyRe (T3nd0s Skyrim Redone) and it's modfied sneak and thiefing trees. I will link it here, just in case you are interested to overhaul your game.

T3nd0s Skyrim Redone by T3nd0
http://www.nexusmods.com/skyrim/mods/9286/?