DomainWatch makes it easy for you to monitor your own domains and ones you want to acquire. We keep an eye on expiration dates, nameservers, SSL certificates, whois contacts and more. DomainWatch is free for monitoring expiration for 10 domains. If you have more domains and want to monitor more than just expiration dates, say hello.
We have started the project during a hackaton here at Themeisle and just managed to launch a beta version for it. While before I was wondering why there aren't any good tools for this, soon I realise that is much more complex than I thought, for now we are using various existing APIs from Godaddy,DomainsBot and DataMuse with custom rules, exclusions and suggestions to make sure we deliver much better results. It seems that the only good solution for now and something we are working on is to integrate MTurk or microworkers and generate suggestions "on-the-fly", while building a nice database of data, I am passionated about ways that we can build a smart searh/suggestion engine "backed" by humans, will see how much it makes sense.
I spend way too long researching and trying to find available domain names. I also wanted to learn Python and Django. So I built this site over the weekend to find available dictionary word domains and sorted them by frequency of use.