you can eat as much as you like of free foods, these are:
on red: lean meat, seafood, most fish and eggs
on green: pasta, potatoes, rice, cous cous, eggs, quinoa etc
please remember though that "as much as you like" does mean eating until you are comfortably full, it doesnt mean stuff your face until you cant get up
there are other foods that are syn free, such as muller lights, certain mugshots etc but its generally agreed that having too much of these will impact on your losses.
i hope thats clear for you

good luck with SW! xx