Dead Man's Switch alternatives

Poke helps users remember things by meeting them where they are. Instead of notifications, your reminders are delivered via text message.

Twitchifier is a app for Windows and Linux (Mac soon), that notifies you with sound as well, as soon as your favorite streamers go on-/offline. It sits in the the taskbar. With two clicks you can pause notifications, see who's online, or add/remove streamers.