Somewhat limited by the shapes of your files, but mostly just your imagination. You don't have to use what they sell as trim, you can just roll your own.
I really like woodworking with hand tools. The possibilities are endless and you are only limited by your ability in customizing the tool and blade you make. Scratchstock cutters, moulding plane blades, even plane blades can be shaped to meet the need exactly. Lots of fun and very satisfying.
True comment. Scratchstocks have the advantage of being able to produce different cutter shapes quickly without the need of getting into annealing, hardening and tempering. It's a slower process.