Rio: Rainbow Gate!

Both are very colorful series, with games as the main theme. Both main characters are unnaturally good at gaming. The main plot in both of them involves the main character to collect an item given to other strong gamers (Gate Cards and Race Pieces) 

Two things, hot chicks and gambling. Plus some plot were it places them hot chicks in very lucky situations. 

Keeping with the theme of girls and various other stuff, this anime is also out of the ordinary. 

Najica Blitz Tactics is like an older version of Rio Rainbow Gate. The most simmilar thing of the serie is that they both have pantyshots the whole serie 

Both of them have special cards and have relation with money. The two of them fight in money battles, money games or money univers. 

In both the animes there are girls which have special abilities in different games. Rio has special powers in poker games and Saki has special powers in mahjong.