Suggest to find all the properties

private static TEnum[] GetAllOptions()
{
Type baseType = typeof(TEnum);
return Assembly.GetAssembly(baseType)
.GetTypes()
.Where(t => baseType.IsAssignableFrom(t))
.SelectMany(t => t.GetFieldsOfType() || t.GetPropertiesOfType())
.OrderBy(t => t.Name)
.ToArray();
}

The issue names only GetAllOptions and its reflection calls; start by locating that entry point and inspecting how GetFieldsOfType is defined. Confirm the intended behavior for discovering both fields and properties, then identify or add tests that establish what counts as a complete result.

Written by the indexing model from the issue text.