This is a great list. But one to add is Tickletrain. It automatically follows up on important emails for you. Before you send your email you just insert a special email address in the BCC field that Tickletrain gives you and that’s it. If you don’t hear back on the email it automatically follows up on it for you- and if you do get a reply the follow up cancels. Super easy and a huge productivity booster. There’s a free plan and the unlimited is $5/mo. I use it when I send quotes and invoices out. Works great. www.tickletrain.com