Find all classes that derive from type and activate that type

I have already looked at some similar answers but I cannot get it to work.

I am attempting to make the following more maintainable:

var modules = new INinjectModule[]
{
    new ServiceModule(),
    new ApplicationSettingsModule(),
    new SerializerModule(),
    new LoggerModule(),
    new SqliteModule(),
    new SetupModule(), 
    new CacheModule(), 
    new AuthenticationModule(), 
};

Every time I add a new NinjectModule I need to modify this array to include it.

I want to be able to find all types that derive from NinjectModule and activate them and put them all into a collection.

This is what I have tried but I am not getting any of my classes that derive from NinjectModule

var classes = (from domainAssembly in AppDomain.CurrentDomain.GetAssemblies()
                from assemblyType in domainAssembly.GetTypes()
                where typeof(NinjectModule).IsAssignableFrom(assemblyType)
                select assemblyType).ToArray();