I know that it seems like he is limited, but actually I think this is pretty good variety. Around that age they really start getting picky. I have an 18 month old too, and I too made all of her baby food and nursed her until 17 months. She is definitely getting pickier and more "set in her ways" when it comes to food. Since I have 5 children I know that this is just a phase, and she will begin eating more eventually. I give my daughter a good multivitamin which really helps to round out her meals, and gives me peace of mind. I highly recommend that.
I know how awful it is to make the same thing meal after meal...my 3 year old is much pickier than my 18 month old, and she pretty much only eats a slice of cheese for dinner...except for the rare occasion when we have tacos or breakfast food with syrup...otherwise she literally screams and acts scared if I try to get her to eat what we are eating. Some kids are like that. I'm looking forward to the day when she eats better, but the doctor isn't worried...even though she is only in the 5th percentile for height and weight.
I think you are doing a great job! Try not to stress over it.