The one south of Cardston is called Carway, and is only open from 7am to 11pm every day. There's also Chief Mountain which is just outside Waterton.
Coutts is the only 24/7 crossing in Alberta. I think most commercial traffic goes through Coutts, so that might mean the other crossings aren't as busy (but they're also not as well-staffed).
Here's a list of all the crossings in Alberta:
http://www.cbsa-asfc.gc.ca/contact/l...dex1587-e.html