You can add it as part of a private blog network or you can 301 redirect an expired domain to your site to bring some trust and authority to your site. Now, in my experience, the best place to look for expired domains is this free website called expireddomains.net. So, you just have to head over there, make a free account and this is the page that you’ll see when you log in.
ExpiredDomains.net gathers all the information you need to find good Expired Domains that are Pending Delete and you can Backorder. Depending on the domain extension you can search through thousands of domains every day before they get released to the public and pick what you like. ExpiredDomains.net currently supports 473 TLDs. From the classic gTLDs like .com, .net, .org to Droplists for ccTLDs you can only find here and now we even support some of the best new gTLDs like .xyz and .club.