D

dagObjectCompare
dagPose
dataStructure
date
dbcount
dbmessage
dbpeek
defaultLightListCheckBox
defaultNavigation
defineDataServer
defineVirtualDevice
deformer
deformerWeights
deg_to_rad
delete
deleteAllContainers 
deleteAttr
deleteAttrPattern
deleteExtension
deleteShadingGroupsAndMaterials 
deleteShelfTab 
deleteUI
deleteUnusedBrushes 
delrandstr
destroyLayout 
detachCurve
detachDeviceAttr
detachSurface
deviceEditor
deviceManager
devicePanel
dgdirty
dgeval
dgInfo
dgmodified
dgtimer
dimWhen
directionalLight
directKeyCtx
dirmap
dirname 
disable
disconnectAttr
disconnectJoint
diskCache
displacementToPoly
displayAffected
displayColor
displayCull
displayLevelOfDetail
displayNClothMesh 
displayPref
displayRGBColor
displaySmoothness
displayStats
displayString
displayStyle 
displaySurface
distanceDimContext
distanceDimension
doBlur
dockControl
dolly
dollyCtx
dopeSheetEditor
doPublishNode 
dot
dotProduct 
doubleProfileBirailSurface
drag
dragAttrContext
draggerContext
dropoffLocator
duplicate
duplicateCurve
duplicateSurface
dynamicConstraintMembership 
dynamicLoad
dynCache
dynConnectToTime 
dynControl
dynExport
dynExpression
dynGlobals
dynPaintEditor
dynParticleCtx
dynPref

indicates a MEL script