You use all-comers to refer to everyone who wants to take part in an activity, especially a competition. This is her second season offering residential courses for all-comers
You can use comers to refer to people who arrive at a particular place. I arrived at the church at two-thirty p.m. to find some early comers outside the main door The first comer was the Sultan himself. see also all-comers, latecomer, newcomer. anyone who wants to take part in an activity, especially a sporting competition