The reign of Maues and his successors saw a renewed prosperity for the Greek kingdoms of India. Maues, Azes, and Abdagases after Azes, were all admirers of Greek culture and favored the Greeks among their many allies. Under Xanthian patronage, the kingdoms were were united in a loose confederation, in 683 AUC (71 BC), known as the Menander League, named after Menander I, who, half a century before, united the Indo-Greek states.
The league could hardly be considered to be a unified polity, but prevented armed conflict between the Greeks, who were also protected from barbarian incursion from the north by Xanthian territory, as well as by the Xanthian support of sedentary states beyond, such as Dahae, Kwarezm, and Sogdiana. In this stable climate, the Indo-Greek states prospered and expanded. At that time, the Indian political climate was chaotic and unstable, as the Sunga Empire which had ruled began to collapse upon itself. The opportunistic Greeks, with tacit support from their Xanthian patrons, were able to capitalize on the situation, expanding their influence south to the mouth of the Indus, and east, into the upper Gangetic plain. True to form, the conquerers were an independent and stubborn lot, and, thus, instead of the new territories being added to existing states, new Greek states were formed, expanding the League in that fashion.
Though the Indo-Greeks continued to squabble amongst themselves, their economy and cities expanded, with great engineering and architectural works being completed during this time, among them many Buddhist monuments. As Buddhism had grown in popularity with the Greeks living in India, as well as the Xanthian royal family (though the Xanthian Empire made few efforts at proselytization)
As the Greeks expanded their holdings, native states began to assert themselves against the possibility of invasion by the Indo-Greeks, congealing into larger empires. Just to the south of the Menander League, the kingdom of Surastrene, or Surashtra, (the Kathiawar peninsula), expanded up to the Thar desert, and along the coastline, until it abutted the Satavahana dynasty. The Satavahanas, for their part, were consolidating their empire across southern India.
Even the failing Sunga dynasty experienced something of a resurgence, with states as far west as Mathura seeking the protection of Devabhuti, the Sunga king. However, Devabhuti, in his eagerness to restore the glory of his dynasty, overextended his resources and presented an appealing target for the kingdom of Kalinga to the south, invading in 696 AUC (58 BC). The war was quick, with the Sunga capital of Pataliputra falling before the end of the year, with the city gates being opened by treachery, and Devabhuti being killed by a slave girl. Kalinga thus took the place of Sunga, without much further resistance, and expanded its influence up the Ganges.
The Indo-Greeks are one of the more interesting anomalies of history, and deserve a little love. Their downfall seems inevitable, given how far they are from their homeland, but they hung on for quite some time; several centuries, in fact. With Maues invading Parthia, instead of the Indo-Greek kingdoms, they get a slight reprieve, which is assisted by the support of Maues himself, as well as his successors. For a comparison, think of the League of Corinth, during Alexander's time, slightly watered down; not direct control, but stability, enforced from the outside.
The rest of India is being shaken around a bit, as it was, anyway. There aren't nearly as many records of Indian kings at this point, so, unfortunately, India, for the most part, won't get the same personal touch as the west does, for some time.