The most popular place by far is ExpiredDomains.net. The main advantage of ExpiredDomains.net is that it aggregates data from a lot of different auctions and websites around the web. There are also paid services like DomCop. DomCom helps you identify worthy domains faster by displaying some additional data points that allow you to vet domains easily and in a unified interface. And finally, there are services that curate domains they believe are worthy such as JustDropped.com’s newsletter.
Wow I didn't expect A War & Peach novel, but, to have about 30 pages this is a very thin offering. My thought is if I get one idea from a $.99 e-book-it made it worthwhile. So there was mention in a keyword tool that might be helpful to me. But, generally speaking, As a s domain investor with sales under my belt, there is very little additional information that I can use here. If you are looking for a fast 10 minutes read this is it. I'd pass.
In the past, expired domains were used as part of black hat SEO in order to generate backlink sources quickly and easily, and this practice is still used somewhat today. Getting links in this way is not a recommendable practice. All relevant search engines work nowadays with highly complex ranking algorithms, which can no longer be outsmarted by these link networks.
There is NO accurate way to predict the sale of digital assets – if someone wants it, they’ll buy it. For example, those wasting their money on useless .com’s (LLLL’s that have no rhyme or reason) will spend 3x more time and money optimizing their useless name as someone that buys ANY keyword loaded domain (regardless if a TLD or new one). But these individuals who are spending thousands on domains will eventually get stuck with these domains in favor of (you guessed it) the oft forgotten yet highly useful 1-3 keyword domains. Why? Study Google’s algorithm as I have for over a decade, and you’ll figure it out.
Review Web Archive’s versions of the website: Examine the website’s history and how it looked like using the Web Archive. What was it about? What did it offer? This is useful for a variety of different reasons. It could inspire you as to who a good potential buyer might be (by analyzing the website’s content), and it could also signal some red flags in case the domain was being used for anything shady.
Length: This is pretty self-explanatory. Generally the shorter the domain name, the more valuable it is. This difference in value decreases exponentially as the name gets longer, though. For instance, the difference in price between 3 and 4 letter domains are significant, while the price difference between a 7 and 8 letter domain would usually be much less significant.