I can’t say I’ve ever really gotten into these, but this site is incredible. It’s got over 26 thousand(!) drawings of skyscrapers, of which over 22 thousand are of existing (i.e. already built) ones.
You can restrict and order the buildings by country, city, size, and a myriad of other criteria. The presentation is just fantastic and some of the buildings are awe inspiring.
Here’s one of my favorites:
It’s called the "Chicago Super Tower". In this case it doesn’t actually exist but is from the creative mind of Eduardo Segundo Hernandez.
Nuttin' 