Build VCL application for macOS and Linux without modifications of sources. Using CrossVcl you focus only on your VCL application and CrossVcl makes it cross-platform.
FmxLinux
Full featured FireMonkey implementation for Linux platform. Using FmxLinux you focus only on your FMX application and FMXLinux makes it available on Linux.
SmartCrashLog
Cross-Platform Application Crash Log Generator and Symbolizer.