Hmm, things like AMP, there’s two plugins that come to mind:
The latest version of WebAPI can run when Minecraft is offline, there might be a way to restart a server with it, if not, I imagine it’s gonna get added sometime not long in the future.
Haven’t tried this plugin, but seems similar.
For server restarts only one I know is leelawd93 / MMCReboot
You could use another plugin, like Simon_Flash / CmdScheduler to have it run every so often. Or even use webapi + a cronjob to do this.