The latest stable release Ubuntu 18.10 with a code name (Cosmic Cuttlefish) has been released. Ubuntu 18.10 comes with 7 different flavours, Kubuntu, Lubuntu, Ubuntu Budgie, Ubuntu Kylin, Ubuntu Mate, Ubuntu Studio, Xubuntu, and the main release Ubuntu with Gnome desktop environment.
Ubuntu 18.10 (Cosmic Cuttlefish) comes with Linux Kernel 4.18 which brings a better support for AMD Radeoan RX Vega M graphics processor, Raspberry Pi 3B/3B+, Qualcomm Snapdragon 845, and a better support for USB 3.2 and USB type-C. Linux Kernel 4.18 provides a better power saving especially for Intel Skylake X servers and KVM support for AMD Secure Encrypted Visualization.
The main release Ubuntu 18.10 comes with Gnome Desktop 3.30 which comes with tons of improvements and user interface polishes comparing to its predecessor with Ubuntu 18.04 LTS (Bionic Beaver).
Check the official release notes of Ubuntu 18.10 (Cosmic Cuttlefish).