Modding Basics

Gamebryo related modding tools. If there's no link it's because you have to buy it.

Another resource here.

Model and animation:

• Nifskope & Nifskope 2.0
• .nif viewer with basic editing options.
• 3dsMax
• Autodesk's 3D modelling program with .nif support.
• Blender
• Popular and free modelling program with .nif support.

Sound:

• Audacity 
• There are many others but this one works for me.
• Skyrim Music Converter
• All-in-one tool for converting TESV music.

Texture:

• Honeyview
• Fastest image viewer I've come across and it has .dds support.
• GIMP
• Free image editing program with .dds support
• Photoshop
• Autodesk's image editor with .dds support.

.ini editing

• Notepad++
• All you really need.
• Brackets
• Heavier and fancier text editor.

Screenshots and video

• Fraps
• Popular capture software.
• Shadowplay
• Nvidia's game capture software(no screenshot support).
• MSI Afterburner
• GPU configuring tool with capture functions.

Graphics related

• SweetFX / Reshade
• Popular and easy to use graphics injector with screenshot support.
• ENB
• Closed source and almost deprecated graphics injector.
• GeDoSaTo
• DX9 downsampling software with other neat funtions.
• Nvidia Inspector
• Nvidia specific utility.
• Radeon Pro
• AMD specific utility with capture funtions.
• SRWE
• Window editor, sometimes it's useful.
• DX9 Image Viewer
• For making SweetFX or Reshade profiles using just an image.
• Screenshot specific Cheat Engine tables
• Most cheat tables just help you cheat but Jim2point0 makes tables that help you take cool screenshots.

.esp/.esm related

• TES 4 Edit
• Fallout 3 Edit
• New Vegas Edit
• TES 5 Edit

Console commands

• Morrowind
• Oblivion
• Skyrim
• Fallout 3 & New Vegas

Oblivion or Skyrim commands that I actually use, off the top of my head

• tgm = toggle god mod
• tcl = toggle collision 
• fov # = field of view
• tai = toggle AI
• tfc = toggle free cam
• tfc 1 = toggle free cam and stop time
• sgtm # = set game time modifier(speed or slow down time)
• twf = toggle wireframe
• ts = toggle sky
• tmm 1 = toggle map markers
• tg = toggle grass
• tm = toggle menus
• tg = toggle character(click on NPC and type this to control it)
• tlv = toggle leaves(Oblivion only)
• set gamehour to # =1-24
• set timescale to # 
• unlock = unlocks locks
• kill/resurrect = kills or resurrects actors
• removeallitmes = removes actor's inventory
• enable/disable = enables or disables objects/actors
• refreshini = reloads the .ini, useful for editing .ini settings during run time
• sucsm # = free camera speed
• mfg phoneme/expression/modifier # = modify facegen
• phoneme 0-15
• expression 0-7
• modifier 0-13
• savepcface name