Windows 8 store apps have access to a number of standard buttons, but for some reason, Microsoft choose not to show what they look like. So here is a complete list of app bar images, and the button names. My only question is, why no down arrow?
And here’s the list of names in the same order. You can also search by prompt in the StandardStyles.xaml file;
SkipBackAppBarButtonStyle SkipAheadAppBarButtonStyle PlayAppBarButtonStyle PauseAppBarButtonStyle EditAppBarButtonStyle SaveAppBarButtonStyle DeleteAppBarButtonStyle DiscardAppBarButtonStyle RemoveAppBarButtonStyle AddAppBarButtonStyle NoAppBarButtonStyle YesAppBarButtonStyle MoreAppBarButtonStyle RedoAppBarButtonStyle UndoAppBarButtonStyle HomeAppBarButtonStyle OutAppBarButtonStyle NextAppBarButtonStyle PreviousAppBarButtonStyle FavoriteAppBarButtonStyle PhotoAppBarButtonStyle SettingsAppBarButtonStyle VideoAppBarButtonStyle RefreshAppBarButtonStyle DownloadAppBarButtonStyle MailAppBarButtonStyle SearchAppBarButtonStyle HelpAppBarButtonStyle UploadAppBarButtonStyle EmojiAppBarButtonStyle TwoPageAppBarButtonStyle LeaveChatAppBarButtonStyle MailForwardAppBarButtonStyle ClockAppBarButtonStyle SendAppBarButtonStyle CropAppBarButtonStyle RotateCameraAppBarButtonStyle PeopleAppBarButtonStyle ClosePaneAppBarButtonStyle OpenPaneAppBarButtonStyle WorldAppBarButtonStyle FlagAppBarButtonStyle PreviewLinkAppBarButtonStyle GlobeAppBarButtonStyle TrimAppBarButtonStyle AttachCameraAppBarButtonStyle ZoomInAppBarButtonStyle BookmarksAppBarButtonStyle DocumentAppBarButtonStyle ProtectedDocumentAppBarButtonStyle PageAppBarButtonStyle BulletsAppBarButtonStyle CommentAppBarButtonStyle Mail2AppBarButtonStyle ContactInfoAppBarButtonStyle HangUpAppBarButtonStyle ViewAllAppBarButtonStyle MapPinAppBarButtonStyle PhoneAppBarButtonStyle VideoChatAppBarButtonStyle SwitchAppBarButtonStyle ContactAppBarButtonStyle RenameAppBarButtonStyle PinAppBarButtonStyle MusicInfoAppBarButtonStyle GoAppBarButtonStyle KeyboardAppBarButtonStyle DockLeftAppBarButtonStyle DockRightAppBarButtonStyle DockBottomAppBarButtonStyle RemoteAppBarButtonStyle SyncAppBarButtonStyle RotateAppBarButtonStyle ShuffleAppBarButtonStyle ListAppBarButtonStyle ShopAppBarButtonStyle SelectAllAppBarButtonStyle OrientationAppBarButtonStyle ImportAppBarButtonStyle ImportAllAppBarButtonStyle BrowsePhotosAppBarButtonStyle WebcamAppBarButtonStyle PicturesAppBarButtonStyle SaveLocalAppBarButtonStyle CaptionAppBarButtonStyle StopAppBarButtonStyle ShowResultsAppBarButtonStyle VolumeAppBarButtonStyle RepairAppBarButtonStyle MessageAppBarButtonStyle Page2AppBarButtonStyle CalendarDayAppBarButtonStyle CalendarWeekAppBarButtonStyle CalendarAppBarButtonStyle CharactersAppBarButtonStyle MailReplyAllAppBarButtonStyle ReadAppBarButtonStyle LinkAppBarButtonStyle AccountsAppBarButtonStyle ShowBccAppBarButtonStyle HideBccAppBarButtonStyle CutAppBarButtonStyle AttachAppBarButtonStyle PasteAppBarButtonStyle FilterAppBarButtonStyle CopyAppBarButtonStyle Emoji2AppBarButtonStyle ImportantAppBarButtonStyle MailReplyAppBarButtonStyle SlideShowAppBarButtonStyle SortAppBarButtonStyle ManageAppBarButtonStyle AllAppsAppBarButtonStyle DisconnectDriveAppBarButtonStyle MapDriveAppBarButtonStyle NewWindowAppBarButtonStyle OpenWithAppBarButtonStyle ContactPresenceAppBarButtonStyle PriorityAppBarButtonStyle UploadSkyDriveAppBarButtonStyle GoToTodayAppBarButtonStyle FontAppBarButtonStyle FontColorAppBarButtonStyle Contact2AppBarButtonStyle FolderppBarButtonStyle AudioAppBarButtonStyle PlaceholderAppBarButtonStyle ViewAppBarButtonStyle SetLockScreenAppBarButtonStyle SetTitleAppBarButtonStyle CcAppBarButtonStyle StopSlideShowAppBarButtonStyle PermissionsAppBarButtonStyle HighlightAppBarButtonStyle DisableUpdatesAppBarButtonStyle UnfavoriteAppBarButtonStyle UnPinAppBarButtonStyle OpenLocalAppBarButtonStyle MuteAppBarButtonStyle ItalicAppBarButtonStyle UnderlineAppBarButtonStyle BoldAppBarButtonStyle MoveToFolderAppBarButtonStyle LikeDislikeAppBarButtonStyle DislikeAppBarButtonStyle LikeAppBarButtonStyle AlignRightAppBarButtonStyle AlignCenterAppBarButtonStyle AlignLeftAppBarButtonStyle ZoomAppBarButtonStyle ZoomOutAppBarButtonStyle OpenFileAppBarButtonStyle OtherUserAppBarButtonStyle AdminAppBarButtonStyle StreetAppBarButtonStyle MapAppBarButtonStyle ClearSelectionAppBarButtonStyle FontDecreaseAppBarButtonStyle FontIncreaseAppBarButtonStyle FontSizeAppBarButtonStyle CellphoneAppBarButtonStyle ReshareAppBarButtonStyle TagAppBarButtonStyle RepeatOneAppBarButtonStyle RepeatAllAppBarButtonStyle OutlineStarAppBarButtonStyle SolidStarAppBarButtonStyle CalculatorAppBarButtonStyle DirectionsAppBarButtonStyle TargetAppBarButtonStyle LibraryAppBarButtonStyle PhonebookAppBarButtonStyle MemoAppBarButtonStyle MicrophoneAppBarButtonStyle PostUpdateAppBarButtonStyle BackToWindowAppBarButtonStyle FullScreenAppBarButtonStyle NewFolderAppBarButtonStyle CalendarReplyAppBarButtonStyle UnsyncFolderAppBarButtonStyle ReportHackedAppBarButtonStyle SyncFolderAppBarButtonStyle BlockContactAppBarButtonStyle SwitchAppsAppBarButtonStyle AddFriendAppBarButtonStyle TouchPointerAppBarButtonStyle GoToStartAppBarButtonStyle ZeroBarsAppBarButtonStyle OneBarAppBarButtonStyle TwoBarsAppBarButtonStyle ThreeBarsAppBarButtonStyle FourBarsAppBarButtonStyle
No down arrow because you should use a transform to flip?
Perhaps, yet there is both a left and right arrow that could also be done with a flip.