https://bizlib247.wordpress.com/2015/10/06/a-quick-look-at-local-and-world-market-indices-in-datastream/

With a wealth of information and functions available, it is easy to miss a few potentially useful commands in Thomson Reuters Datastream. Here are some examples relating to local equity indices and global ones. (This post assumes you are familiar with the basics of Datastream; please see the getting started guides or other posts for more.)

World Market Index (TOTMKWD and others)
On a related but different note, it is possible to use many international and global equity indices that have been constructed in Datastream. One such index is the top level World-Datastream Market (TOTMKWD), covering over 6,000 active constituent entities.

There is a systematic set of codes for various countries, blocs and combinations, for all or selected sectors. They are also findable in the Navigator (see image above) and usable as any other Equity Index. The first five characters represent the sector, the last two digits represent part of the world, so you could use combinations such as the following.
For the World market index at level 1 use: TOTMKWD
For the French financials industry index at level 2 use: FINANFR
For the Europe banks sector at level 6 use: BANKSER
For full details, go to the Datastream Extranet (via the Datastream Desktop application) and search for “Global Equity Indices User Guide”.

http://libguides.princeton.edu/c.php?g=84214&p=545184

The following provide data under the Global Indices section:
Datastream Global Indices, Jardine Fleming Small Cap Indices, ING Barings Emerging Markets, M.S.C.I. Indices, Cazenove Rosenberg Small Companies, Nomura East European indices, Dow Jones Global Indices, Private Investor Indices, FT/S&P World Indices, GPR-Life Real Estate Securities, European Indices, IFC Emerging Markets, HSBC Securities Indices, and Salomon Smith Barney World Equity.

next to be MSCI index for developed and emerging

MSCI World Investable Market Index (IMI):

FLAGSHIP BENCHMARKS
MSCI World Index: Covers more than 1,600 securities across large and mid-cap size segments and across style and sector segments in 23 developed markets.
Performance | Factsheet
MSCI World Investable Market Index (IMI): Covers more than 4,500 securities across large, mid and small-cap size segments and across style and sector segments in 23 developed markets.
Performance | Factsheet
MSCI World All Cap Index: Covers a comprehensive set of approximately 6,100 securities and includes large, mid, small and micro-cap size segments for all 23 developed markets countries.
Performance | Factsheet

world=developed

acwi = d+e

imi = common+small