My DS is PG. We had great luck with board books that had photos in them rather than cartoon drawings. Because it was real, we could sit and talk about the pictures in great detail.
Eventually, we started a game with the books - find a picture of a tractor progressing to find a picture of a red tractor in a book that also has a watermelon on a blue tablecloth.... LOL He had a whole pile of books and he had them memorized. Loved finding the right book. That kept us going until he was old enough (11 mo) to give the picture dictionary with photos in it.
He also loved counting - couldn't say the words right, but loved counting nonetheless. I would throw these plastic kid-safe fish on the floor and count them as he picked them up and put them in the bucket. Eventually, he started throwing them over his left shoulder as he counted himself - uh doo dee doh dye di dede... you get the idea. It was quite cute.
As for the bathtub letters - DS tried to eat them and we had to take those away. By 12 months, he stopped putting books in his mouth - but everything else went in his mouth and we had to be very careful about what we gave him.
Keep in mind that no matter how smart - he is still a baby and needs to learn all the same things as normal babies (except the things he has already mastered). That includes things like how to focus on a picture to see it and how to move and grab and such. Motor skills are easy to ignore.
Mostly, we stuck with regular age appropriate toys - just found more creative and interesting ways to play with them.
Mary
