Visual Studio Code list of keyboard shortcuts options

These are hopefully all variables that can be used in when conditions:

editorFocus
editorHasMultipleSelections
editorHasSelection
editorLangId == 'name' // for example: editorLangId == 'typescript' 
editorTabMovesFocus
editorTextFocus
findWidgetVisible
globalMessageVisible
hasWordHighlights
inChangeAllMode
inDebugMode
inQuickOpen
inReferenceSearchEditor
inSnippetMode
markersNavigationVisible
parameterHintsVisible
peekDeclarationVisible
quickFixWidgetVisible
referenceSearchVisible
renameInputVisible
searchViewletVisible
suggestWidgetVisible
textCompareEditorVisible

You can concat them with && and invert them with !. For example

editorTextFocus && !editorTabMovesFocus 

Updated. April 2019 (version 1.34)

List of all variables that can be used in when conditions in version 1.34:

acceptSuggestionOnEnter
accessibilityHelpWidgetVisible
activeEditor
activeEditorGroupEmpty
atEndOfWord
breadcrumbsActive
breadcrumbsPossible
breadcrumbsVisible
breakpointSelected
breakpointWidgetVisible
breakpointsFocused
callHierarchyVisible
commentEditorFocused
config.breadcrumbs.enabled
config.editor.stablePeek
config.editor.tabCompletion
config.emmet.triggerExpansionOnTab
config.gitlens.keymap
debugConfigurationType
debugState
debugType
dirtyDiffVisible
editorFocus
editorHasCallHierarchyProvider
editorHasCodeActionsProvider
editorHasCompletionItemProvider
editorHasDefinitionProvider
editorHasDocumentFormattingProvider
editorHasDocumentSelectionFormattingProvider
editorHasImplementationProvider
editorHasMultipleSelections
editorHasReferenceProvider
editorHasRenameProvider
editorHasSelection
editorHasSignatureHelpProvider
editorIsOpen
editorLangId
editorReadonly
editorTabMovesFocus
editorTextFocus
explorerResourceCut
explorerResourceIsFolder
explorerResourceIsRoot
explorerResourceMoveableToTrash
explorerResourceReadonly
explorerViewletFocus
explorerViewletVisible
expressionSelected
fileMatchFocus
fileMatchOrFolderMatchFocus
fileMatchOrMatchFocus
filesExplorerFocus
findInputFocussed
findWidgetVisible
firstMatchFocus
folderMatchFocus
gitlens:activeFileStatus
gitlens:canToggleCodeLens
gitlens:enabled
gitlens:key:,
gitlens:key:.
gitlens:key:escape
gitlens:key:left
gitlens:key:right
hasNextTabstop
hasOtherSuggestions
hasPrevTabstop
hasSearchResult
hasSnippetCompletions
hasWordHighlights
historyNavigationEnabled
historyNavigationWidget
inBreakpointWidget
inDebugMode
inDebugRepl
inEditorsPicker
inFilesPicker
inKeybindings
inKeybindingsSearch
inQuickOpen
inRecentFilesPicker
inReferenceSearchEditor
inSettingsEditor
inSettingsSearch
inSnippetMode
inViewsPicker
inZenMode
inputBoxFocus
inputFocus
interactivePlaygroundFocus
interfaceOverviewVisible
isDevelopment
isInDiffEditor
isInEmbeddedEditor
keybindingFocus
listFocus
listHasSelectionOrFocus
listSupportsMultiselect
markersNavigationVisible
matchFocus
messageVisible
multipleEditorGroups
notificationCenterVisible
notificationFocus
notificationToastsVisible
parameterHintsMultipleSignatures
parameterHintsVisible
problemFocus
problemsFilterFocus
problemsViewFocus
python.datascience.featureenabled
python.datascience.hascodecells
python.datascience.ownsSelection
reference-list.hasResult
referenceSearchTreeFocused
referenceSearchVisible
remoteFileDialogVisible
renameInputVisible
replaceActive
replaceInputBoxFocus
replaceInputFocussed
scmRepository
searchInputBoxFocus
searchViewletFocus
searchViewletVisible
settingsTocRowFocus
suggestWidgetMultipleSuggestions
suggestWidgetVisible
suggestionMakesTextEdit
supportedCodeAction
terminalFindWidgetFocused
terminalFindWidgetVisible
terminalFocus
terminalTextSelected
textCompareEditorVisible
textInputFocus
variablesFocused
watchExpressionsFocused
webviewFindWidgetVisible
workbench.explorer.openEditorsView.active