Board books, touch and feel books, pull/slide books, books with finger puppet. These are a few types I have, but just a normal picture book with lots of bright colors is also perfectly fine as long as you read it to baby. I usually borrow from library but during this period I guess you can try online kinokuniya, popular or book depository.
https://shopee.sg/product/48685683/3100322029?v=990&smtt=0.0.3 I bought quite a number of cloth books fr shopee at a cheap price from the above link. Can also try q0010.