Counters can be discs of plastic - rather like tiddly-winks - or can be representational of some part of your game.  It would be easy to make small rocket ships from dowel or acrylic rod, if you were making a space game.  You could even reduce the diameter at one end so that the counter became more like a peg -that way the shape would never move around… perhaps an important consideration for a travel game ?

Simple shapes like triangles, stars, squares and circles - in different colours - can be simple to make and effective in most games.  Discs could be made to fit into small slots rather than lying flat on the playing board.  Look around you for inspiration.

Of course the board on which the game is played will need to be designed too - and it must fit in the box.

There could be several solutions to the task of creating a board.  Jigsaw pieces can be put together to make a larger playing area than the individual pieces occupy when stored.

Another possible solution might be to design a treasure map - a roll of fabric onto which a map had been printed.  The design might be 'ironed-on' or screen printed.   Printing blocks might be made using CNC equipment - again printed onto fabric.

Fabric hinges are a possibility and would allow several thin sections of ply to be folded together.  There really are many solutions and a little imagination can result in some great new game boards.