@TERADOMAIN Totally agree with you , I am waiting for the LLL.io buyout , Most of the good ones are already gone . But if the others are also gone soon , the price hike will occur sooner . Meaning more profits for us all :)
use godaddy appraisal tool for checking its approximate value and if you want to sell them list them on godaddy itself or you can try making an auction here on namepros or on digital point.
You can auction it here on Namepros as well but if you are looking for some other options you can try Flippa, Godaddy, Ebay, Sedo marketplace. These are some of the well known websites where you can auction them easily.
Many sites are available for this purpose, I found a suitable domain name for myself on HOSTGATOR.IN and I think it works really well, even shows related keywords rather than your search that are available at the moment. You can also check some other sites like-
Google domains
Nimtools.com...
Preferences are different according to the needs of people or organisations, but the most worldwide used domain is dot com only but In case, you wanna use domain according to your country you can use them as well. China’s one the biggest site “Alibaba” uses a dot com domain but you can even try...