I see lots of .org names where the .com is available. Most of the .org's don't want the .com because it would make them seem too commercial when they are non-profits. A lot of them are 4-6 letter acronyms with little value in the .com.
If there is no copyright infringement, they might be worth looking into for traffic if the traffic would be targeted enough to get clicks.
Sometimes, you'll find the .com was dropped by the same owner who had the other tld's. They just regged the .com first, and the other TLD's will be dropped later since they were regged later. In fact all are worthless. Sometimes they are valuable, but you have to do your homework to find out.