Terraform error Reference to “count” in non-counted context for resources not necessarily data
looks like your new to stack exchange. You need to form a clearer question to get a good answer.... 

As far as your error goes.... count is a reserved name. It's only accessible when the block you're writing has a count set! 

You have You just need to specify the count of aws_internet_gateway data resources you're trying to get. Your code implies there is more than one.

data "aws_internet_gateway" "zyz_igw" {
   count = 1000000000
   ...