So here a list of the tallest planned, buildings under construction or already built skyscrapers. Just writing for random reasons. I searched Skyscraperpage and Skyscrapercity for information, but still skipped some unlikely buildings and also only featured buildings with a hight of 530m and higher.
Kingdom Tower (Jeddah) - 1000m+ - Planned
There were previous news on the building starting construction 3 weeks later, but it didn't. There are reasonable rumors, that there was a ground testing that gave caused more problems. Currently the project seems to stand still. But in summer Cityscape Jeddah might give it a chance for a real start.
Burj Khalifa (Dubai) - 828m - Build 2010
The currently tallest structure on earth has no thread by any skyscraper or even tower at the moment. It might change when KT starts, but for now it stays the tallest one.
India Tower (Mumbai) - 720m - Under Construction
The tallest building that is currently under construction. The working is still on ground level and the problem about India and skyscrapers is that it is hard to get news and updates.
Shizimen CBD Tower (Zhuhai) - 680m - Planned
Not much information
Sky City (4 cities in China) - 666m - Planned
With new technology it is planned to build 4 of these monsters in rapid speed in four major cities. Wether it is just vision or actually feasable soon is written in the stars.
Baietan Tower (Guangzhou) - 650m - Planned
Standing between Guangzhou and Foshan, a new business district where this tower is located will probably link both cities making them one even bigger one.
Pingan International Finance Centre (Shenzhen) - 648m - Under Construction
The Construction was slow when it started, but soon the project might catch up more speed.
Light Tower (Seoul) - 640m - Planned
More than unlikely, because South Korea yet disappointed a lot before with projects of similar height that never came true.
Shanghai Tower (Shanghai) - 632m - Under Construction
Probably the most exiting building at the moment, because it is fast rising at the moment and when it is finished it will take the second place for the tallest skyscraper for a while.
Tianlong Fortune Center (Nanning) - 628m - Planned
Abraj Al-Bait (Mecca) - 601m - Nearly Finished
The most massive hotel building in a city that features no other nameable skyscrapers due to the special situation the city is in with its millions of tourists.
151 Incheon Towers (Incheon) - 601m - Probably Cancelled or shortened
It was one of my favorite projects, but still South Korea is South Korea and the project will most likely not rise at all.
Shenzhen International Trade Center (Shenzhen) - 600m - Planned
I read today that it might need to get changed and shortened, but still there are no official statements. Just a matter of time to find out though.
Goldin Finance 117 (Tianjin) - 597m - Under Construction
The Construction is slow, but it will catch up speed soon i guess
Lotte World Tower (Seoul) - 555m - Unlikely
Doha Convention Center (Doha) - 551m - Hard to find any news
Freedom Tower (New York City) - 541m - Under Construction
It is growing fast and brings the World Trade Center back to New York.
Chow Tai Fook Centre (Guangzhou) - 530m - Under Construction
It is on ground working and slow, but may turn up the speed after CNY. Guangzhou has a huge building boom and just finished the tallest tower in the world (soon to be topped by Tokyo though)
Chow Tai Fook Binhai Center (Tianjin) - 530m - Planned
Preparation already started. When it gets build it stands about 60km away from Goldin Finance.