What email marketing platforms are best for a small business that needs to handle a large number of subscribers but only runs basic campaigns?

We ask the same underlying question in different ways.

• What email marketing platforms are best for a small business that needs to handle a large number of subscribers but only runs basic campaigns?
• Can you recommend email marketing tools for a small company that has a large database of contacts but keeps their campaigns very basic?
• I run a small business with a huge subscriber list, but I don't need complex automation. What email marketing tools should I look at for simple campaigns?