The ink is barely dry on the merger deal between CBS Corp. and Viacom Inc., and already Wall Street is anticipating which moves the combined company will make to bulk up further in an entertainment industry dominated by a few giants.

Executives at the companies have contemplated the idea of mergers with cable programmers including Discovery Inc. and premium network Starz or its owner, Lions Gate Entertainment Corp. , people familiar with the situation say. Sony Corp.’s movie and TV unit, Hollywood studio MGM and AMC Networks Inc. are among other possible targets, industry executives and Wall Street analysts say.

The planned merger of CBS and Viacom brings together Viacom’s several major cable channels including MTV and Nickelodeon—and its movie studio Paramount Pictures—with CBS’s flagship broadcast network and premium cable channel Showtime, among other assets.

The combined company would still be much smaller than competitors that have separated themselves from the media pack through major deals. AT&T Inc., which acquired DirecTV and Time Warner Inc. in recent years, has a $254 billion market capitalization, while Walt Disney Co. , which last year took over the bulk of 21st Century Fox, is valued at $246 billion. CBS and Viacom have a combined value of $30 billion.

The larger media players believe their scale—both in terms of financial heft and in the vast reservoirs of content they control—will help them compete with streaming-video juggernaut Netflix Inc. as more consumers cut the cable-TV cord.