The best alternatives to Mailswipe are Unsubscriber for Gmail, mailfloss, and Plain. If these 3 options don't work for you, we've listed a few more alternatives below.
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Agree.com— Free e-signature for everyone with invoicing and payments!
An opinionated take on what should be a simple, minimal, but efficient reading app, for people who declared Pocket/Instapaper bankruptcy. It only shows the first article in your queue, forces you to decide whether to read or archive the pages you saved, one at a time, and encourages you to let go of the old articles you procrastinate reading.