Diamond Chess is a free and ad free client for Mac, and Android to play chess online. Users can get a free account at FICS. For quick chess games with no-signup just play with the connect as guest option.
The latest android build is diamondchess1.66.apk .
The latest build is Diamond on Mac 2.21 installer.
Some tips are scroll the console with the mouse scroll wheel, use the options button on the board to unlock what the board can do, and use the Action button on top of board for context sensitive commands to do when playing or not playing or observing etc.
Diamond uses the ~/Library/Containers/mike.pearl.chess/Data/Documents/ folder to save PGN. It saves all played games there. You can use the finders Go menu - Go to Folder option with that path to get to your pgn.
lanternbugs at gmail for support

