What common patterns should I look for in chess? When I started learning, I had lots of games where I lost lots of material through not being familiar with these sneaky attacks. I am talking about these:



There are many more (two minor pieces being attacked by a single pawn, discovered checks that result in attacking important pieces, etc)

I think it will be of great help to study them again and have them freshly in my mind (they often go unperceived, both when spotting them, and stopping them).
What you here call 'patterns' are more commonly called chess tactics. See the Wikipedia article for Chess Tactics for a list with some visualization.

These are the simple patterns. There are more complicated patterns that arise rather less commonly, but these complicated patterns tend to simply be a composite of the 'basic tactics'.

A fine example of a more complicated pattern is the windmill: Wikipedia article for Windmill