Language

Math

MEL Math-Related Commands (abs, sqrt, etc.)
abs
angle
bessel
ceil
clamp
constrainValue
cos
cross
crossProduct 
deg_to_rad
delrandstr
dot
dotProduct 
equivalent 
equivalentTol 
erf
exp
floatEq 
floor
fmod
gamma
gauss
getLastError
getProcArguments
hermite
hsv_to_rgb
hypot
linstep
log
mag
max
min
noise
normalize 
pointMatrixMult 
pow
rad_to_deg
rand
randstate
rgb_to_hsv
rot
seed
sign
sin
smoothstep
sphrand
sqrt
tan
trunc
unit

Strings

MEL String-Related Commands (substr, catenation, etc.)
appendStringArray 
basenameEx 
capitalizeString 
clear
containsMultibyte 
copyArray 
encodeString
endString 
endsWith 
format
gmatch
interToUI 
isValidString 
match
size
sizeBytes
sort
startString 
startsWith 
strcmp
stringArrayCatenate 
stringArrayContains 
stringArrayCount 
stringArrayInsertAtIndex 
stringArrayIntersector
stringArrayRemove 
stringArrayRemoveAtIndex 
stringArrayRemoveDuplicates 
stringArrayRemoveExact 
stringArrayToString 
stringToStringArray 
strip 
substitute
substituteAllString 
substring
tokenize
tokenizeList 
tolower
toupper

Scripting

MEL Scripts
assignCommand
catch
catchQuiet
commandEcho
condition
connectControl
deleteUI
dimWhen
disable
error
eval
evalDeferred
evalEcho
executeForEachObject 
exists
isTrue
isValidObjectName 
itemFilter
itemFilterAttr
itemFilterRender
itemFilterType
lsUI
objectTypeUI
optionVar
pause
print
python
refresh
renameUI
scriptJob
selectionConnection
setParent
setUITemplate
source
stackTrace
trace
uiTemplate
waitCursor
warning
whatIs