Developer Yaroslav Brovin has an updated version of his FGX component suite for Firemonkey in Delphi 10 Seattle available. The component suite started out around an activity dialog and a progress dialog component and now has quite a few other must have components for Android and IOS in it as well. There is an instant messaging display class called TfgToast. There is an image flipping component called TfgFlipView with mulitple effects for switching between photos. There are three helper animation TfgPositionAnimation,  TfgPosition3DAnimation, TfgBitmapLinkAnimation components. Of coarse there is TfgProgressDialog and TfgActivityDialog for showing progress and activity dialogs using the native dialogs on each platform. TfgColorsPanel and TfgGradientEdit are provided for selecting colors. And lastly, TfgLinkedLabel is for opening web browser links, TfgApplicationEvents is for providing easy access to the app events, and TfgVirtualKeyboard is for allowing you to access and customize the virtual keyboard. The FGX component suite is free and some of the components should probably work on all four platforms which are Android, IOS, OSX, and Windows. The description information about the component is in Russian so use a browser translator if needed.
Mirror: Download it from Github.
Not to mention the must-have TActionSheet component which I cannot believe isn’t available in Firemonkey yet.