Hi,
We won't add a list based sending method. That's in our TODO list but we only have a few users asking for it (less than 2 users over the year). So I don't know when this will be implemented. Except if someone needs it urgently so we can go for a custom development ;-)
However we will add some new sending method integrations such as SendInBlue, Sendgrid etc.
We've also found new ways to speed up the send process ;-)