Searching in the games in the waiting room is possible using the filters in the table-head of the table list.
 
The default search shows the games, that are suitable to join. That search is built by checking the restrictions of the game offer. Non-suitable games are shown with a red background.
 
The links at the page bottom let you switch between showing all games and all games suitable for you. The page title reflects the current selection with "Suitable waiting games" or "All waiting games".