Some tea drinkers like to steep loose tea leaves in the little metal tea balls attached by a chain to a hook. Here's a couple of lids designed with an inside loop that will take a tea ball hook.
When I sell these teapots, I always include the teaball. They are inexpensive and can be bought in bulk from suppliers.
Another thing a potter can do that commercial tea pot manufacturers don't do is make a matching tea bag saucer to go with the pot. It's just a nice touch.