It would be handy to have a list games which are safe to delete without losing progress. The few which upload saves to iCloud (which isn't the same as iCloud sync) are pretty well documented; there are a number of games, though, which use some other tecnique. Sometimes they will pull info from Gamecenter, other times they use proprietary servers, and sometimes I think it's just magic. Many of these include consumables and save the amount you have as well. Off of the top of my head and having tested them myself, it's safe to delete (while saving all progress) and reinstall: Triggerfist Alien Warfare ...a free shooter by, is it PikPok? argh, memory problems. Ravensword (if you provide an email adress for the cloud server) Please, anyone, feel free to add more. Those of us with limited free space salute you!
Pretty much every game which runs on its own server...? And just a correction: Ravensword doesn't have the cloud feature, you're probably thinking of either Ravensword 2 or Aralon.
Maybe I should have limited to games which pull down info from Gamecenter. Obviously games which have their own server will keep track of your data; there are some though which use Gamecenter.
I know this isn't completely related, but I love this app so much that I feel the need to recommend it in this thread. If you are jailbroken, download DataDeposit and make a free Dropbox account. DataDeposit compressed and stores save data in your dropbox account, makes it VERY simple to backup and restore. It also lets you share data between devices.