I'm trying to educate my colleagues in the area of design patterns.  Some of the original Gang of Four patterns are a little esoteric, so I'm wondering if there is a sub-group of essential patterns that all programmers should know. As I look through the list, I think I've probably used -Abstract Factory Factory MethodSingleton Bridge Facade CommandWhich ones do you actually use in practice, and what do you use them for? Link for those wanting a list of patterns
GoF Design Patterns - which ones do you actually use?
design patterns
Here's a list of which ones I've used or seen in practice:Singleton - Application object in ASP.Net being a prime example of this.Adapter - Connecting to databases usually can involve an Adapter class at least in my area of .Net stuff.Factory - General for generating objects though I saw this more in some older classic ASP back in the day.Strategy - I had an application which for each type of device I had a similar structure for the class that I'd consider an implementation of this pattern.Facade - In some ways this is similar to the Adapter pattern in terms of being something that ties together a couple of systems usually.