Great list of resources. I’d just like to add that nowadays is also important to consider every tool in terms of the data we can get access to, to perform analytics, calculate KPIs etc. So before we select a tool or platform we should also pay attention on the APIs it exposes and how easily we can get data out of it. Even if we don’t plan to use the data right away we most certainly need to do so in the future. You can also check this post here where the different email marketing application/platforms categories are discussed from the data perspective.