In Europe, Nuvoton (ex-Winbond) is a lesser-known manufacturer of ARM Cortex-M0- and Cortex-M4-based microcontrollers (and, traditionally, a wide range of 8051-derivatives).
There is a range of development boards available for each family. The simplest ones are Called "NuMicro SDK (Starter Development Kit)", containing on one board the target processor with several peripherals, and a debugger called NuLink as a detachable piece. The accompanying software package besides the compulsory CMSIS files and examples contains also a library, in a structure not dissimilar to ST's "Standard Peripheral Library". The examples come for IAR and Keil. There is some free (as in free beer) support for these chips/boards and also for the debugger within CooCox/CoIde although not to the extent of the two leading commercial IDEs.
LED/RTC demo for NuTiny-SDK-Nano130 ported for CoIDE v1 and for native gcc/make.
USB demo for NuTiny-SDK-Nano130 ported for CoIDE v1 and for native gcc/make.