The Goughnuts K9 Cup is a great alternative to Kongs. They hold a lot more food and one end is closed so you can be super creative with fillings. My dog can only have his dry kibble right now (trying to figure out allergies) so I soak the kibble in water, use an immersion blender to turn it into mush, fill the cups, and freeze them. I defrost one for 30-60 minutes before giving it to him and it keeps him busy for hours.
My dog isn't really into toys, but he loves to chew antlers. The split ones with exposed marrow are especially appealing to him. Sometimes I stick a thinner antler into the K9 Cup so it sticks out the end and he has to lick around it to get the food out.