Some candidates fr the East (way to the East
)...
1) The Tibetans - their probable ancestors, the Chiang and Di tribes, as recorded in Chinese histories, had been around since even before a recognizable China had been around. In the 7-9th centuries, they expanded aggressively, fighting against the Tang dynasty of China, from hitting Chinese outposts in Central Asia all the way to raiding the province of Sichuan far to the east. Later on, they're also the religious figurehead of the Mongols (fr maybe the 17th century onwards). And Tibet is still around today, sort of.
2) The Uighurs - the most civilised of the Turkic tribes. They were the paramount power in Mongolia, until driven out to Xinjiang in the 9th century, where they settled down into civilised life. They maintained their steppe credentials, and were a great civilising influence on the steppe world. The Mongols even used their script as the basis of their own writing system. Still around today, as a part of modern China.
3) The Sogdians of Central Asia. Don't know much about them, except they're great traders on the Silk Road. Central Asia was once the world's premiere international land trade route, in the form of the Silk Road. Many cities and great centers in this region.
4) The Vietnamese - after freeing themselves fr Imperial China in the 3rd century AD, they'd expanded southwards. A hardy people, who'd fought off the native Chams, drove the Khmers back towards Cambodia, struggled with the Thais over their common borderlands and over Cambodia. More importantly, they'd fought (and won) against the Chinese, French, Japanese and Americans within this century alone. A hardy people.
5) Thailand - there'd always been a series of Thai kingdom since the first one was reliably recorded to be set up in Dali, in what's today Yunnan, China. They fought/migrated their way down to modern Thailand. Always been independent, when all other countries around them fell to the European powers. Arch enemies of the Burmese.
6) The Burmese - arch enemies of the Thais, they'd long established kingdoms in present-day Burma. Had survived invasions by the Mongols, Manchus and occasionally Chinese.
7) The Javanese - their Majapahit kingdom once ruled almost the entire modern Indonesia, plus Singapore and W Malaysia in the 13th century. Today, the heartland and motor of modern Indonesia, one of the more populous nations in the world.
Nice try. 
