Stick to very lean or trimmed cuts of meat to keep them free. Even bacon medallions may require some extra trimming. Always cook without additional fats and oils. Always remove skin from poultry and drain any mince after cooking.
Bacon (back/very lean)
Beef
Beef mince, lean, 5% fat or less
Chicken (Skinless)
Duck
Gammon
Goat
Grouse
Guniea Fowl
Ham
Hare
Heart
Kidney
Lamb
Liver
Oxtail
Partridge
Pheasant
Pigeon
Pork
Pork mince, lean, 5% fat or less
Quail
Rabbit
Turkey
Turkey mince, lean, 5% fat or less
Veal
Venison
Source: https://fatgirlskinny.net/syn-free-foods-slimming-world-essentials/