タブでメソッド一覧が確認できる。

scala> val l = List(1,2,3)
l: List[Int] = List(1, 2, 3)

scala> l.

++                                  +:                                  -                                   --
/:                                  :+                                  ::                                  :::
:\                                  addString                           andThen                             andThen$mcDD$sp
andThen$mcDI$sp                     andThen$mcDL$sp                     andThen$mcID$sp                     andThen$mcII$sp
andThen$mcIL$sp                     andThen$mcLD$sp                     andThen$mcLI$sp                     andThen$mcLL$sp
andThen$mcVD$sp                     andThen$mcVI$sp                     andThen$mcVL$sp                     andThen$mcZD$sp
andThen$mcZI$sp                     andThen$mcZL$sp                     apply                               apply$mcDD$sp
apply$mcDI$sp                       apply$mcDL$sp                       apply$mcID$sp                       apply$mcII$sp
apply$mcIL$sp                       apply$mcLD$sp                       apply$mcLI$sp                       apply$mcLL$sp
apply$mcVD$sp                       apply$mcVI$sp                       apply$mcVL$sp                       apply$mcZD$sp
apply$mcZI$sp                       apply$mcZL$sp                       asInstanceOf                        break
canEqual                            collect                             companion                           compose
compose$mcDD$sp                     compose$mcDI$sp                     compose$mcDL$sp                     compose$mcID$sp
compose$mcII$sp                     compose$mcIL$sp                     compose$mcLD$sp                     compose$mcLI$sp
compose$mcLL$sp                     compose$mcVD$sp                     compose$mcVI$sp                     compose$mcVL$spcompose$mcZD$sp                     compose$mcZI$sp                     compose$mcZL$sp                     contains
containsSlice                       copy                                copy$default$1                      copy$default$2
copyToArray                         copyToBuffer                        corresponds                         count
diff                                distinct                            drop                                dropRight
dropWhile                           elements                            endsWith                            equalsWith
exists                              filter                              filterNot                           find
findIndexOf                         findLastIndexOf                     first                               firstOption
flatMap                             flatten                             foldLeft                            foldRight
forall                              foreach                             genericBuilder                      getClass
groupBy                             grouped                             hasDefiniteSize                     hd$1
head                                headOption                          indexOf                             indexOfSlice
indexWhere                          indices                             init                                intersect
isDefinedAt                         isEmpty                             isInstanceOf                        isTraversableAgain
iterator                            last                                lastIndexOf                         lastIndexOfSlice
lastIndexWhere                      lastOption                          length                              lengthCompare
lift                                map                                 mapConserve                         max
min                                 mkString                            newBuilder                          nonEmpty
orElse                              padTo                               partition                           patch
prefixLength                        product                             productArity                        productElement
productElementName                  productElements                     productIterator                     productPrefix
projection                          reduceLeft                          reduceLeftOption                    reduceRight
reduceRightOption                   remove                              removeDuplicates                    repr
reverse                             reverseIterator                     reverseMap                          reverse_:::
reversed                            reversedElements                    sameElements                        scala$collection$immutable$::$$hd
scanLeft                            scanRight                           segmentLength                       size
slice                               sliding                             sort                                sortBy
sortWith                            sorted                              span                                splitAt
startsWith                          stringPrefix                        sum                                 tail
take                                takeRight                           takeWhile                           thisCollection
tl                                  tl$1                                tl_=                                toArray
toCollection                        toIndexedSeq                        toIterable                          toIterator
toList                              toMap                               toSeq                               toSet
toStream                            toString                            toTraversable                       transpose
union                               unzip                               updated                             view
withFilter                          zip                                 zipAll                              zipWithIndex