Looney Tunes and Hanna Barbera are owned by Turner Broadcasting, which is in turn owned by Time Warner and has been since 1996.
Paramount is owned by Viacom, which they got from the 2005 split from CBS Corporation.
There really aren't a lot of smaller independent players left. The ones that are coming to mind for me are really small, like Amblin Partners, The Weinstein Company, Chernin Entertainment and Blumhouse Productions. Lionsgate is probably the largest independent media company I can think of that isn't the subsidiary of something else.
Now if we're talking blockbuster mega-mergers, I think a Comcast-Verizon merger would be a very big one.