Al Moe mentioned that one of the first locations Harrah opened in Reno was Plaza Tango, so Plaza in Venice may have been a kind of Tango game.

One of the most successful operators was John Harrah and his son Bill. The former Venice mayor was badly in debt after the stock market crash, yet owned mortgages on a number of beach properties far above their deflated value. One such property was the Plaza building at the entrance to the Venice Pier. At the time it housed mostly bowling alleys and a pool hall. They decided to use part of the empty space to open up a variation of bingo which they called the "Circle Game." Players sat at a large circular style bar during the game and marked their bingo cards. A revolving game board with its connecting runway was placed in the center. Each player in turn determined the next number by rolling a ball down the runway so that it landed into one of the numbered slots. The 32 seat parlor grossed $100 the first night it opened on July 4, 1932. The Harrahs were so successful that they soon opened a second game called Tango, then a third.

In 1934 the state passed a law outlawing bingo as a game of chance at his parlors and others that lined the coast. The police and county sheriffs raided the games to shut them down. The arresting officer became confused when Harrah's game didn't even look like bingo. They managed to stay open nearly six months after everyone else was closed by constantly changing the games and keeping one step ahead of the law.

From The Beginning of an Empire by Paul Tanck:

Meanwhile, the Venice Pier continued to pull in crowds of revelers looking for inexpensive excitement all through those years. Others had evolved the old bingo-styled game into a variation called Bridgo. These parlors with exotic names such as Carneo, Vogue, Shamrock, and Canasto were a variation of the same old con game that kept popping up in the beachfront amusement zones. Another front for penny-ante crime, mechanical horse races, were shut down when investigators exposed their fixed wirings. The “sucker games” were wiped out in Venice when a final courtroom test put a clampdown on the rackets in 1949.

This info, plus the way the names were featured on Harrah's Venice matchcover lead me to believe the names were specific gaming parlors with these names on the Venice pier and not necessarily the name of the games themselves.