In the stock market, a Blue Chip is stock in a company with nationwide reputation for quality, reliability and the ability to operate profitably in good times and bad.
So in my view in the real estate sector of Pakistan, the definition of "Blue Chip" will apply to developers with:
(i) Excellent reputation
(ii) Very strong financial credentials.
Which developers fit this description? To me the Blue Chip Developers will be DHA, Bahria, Multi, Emaar (they do have a few properties in Pakistan) ...
Any others?
Eden in Lahore?
Eden is big big fraud, stay away from schemes
Mr PK1, you have rightfully mentioned the best developers!! Nothing to add in it. :).
@ Badmint you are very right about Eden, i have even seen a complaint site, which tells you a lot about EDEN.
But what about any big names of Karachi. Madinawalas? They have also done projects in Islamabad?
Karachi, if you talk about appartments. Saima is a know name for middle class buyers. And they have some good projects close to gulistan e jahur. But i say again spending 7 million on appartment is not a good idea. Better go for a plot in isloo/pindi or lahore. 
@pk1 brother agreed. All of developers u mentioned are blue chip one’s.
DHA, Bahria, MPCHS.