Develop an appreciation for the outdoors and exploration and identification of plants, animals etc when young. DD had one of those kits with a notebook, tweezers, magnifying glass and other items to go outside and explore when young.
Chemistry kit was also a hit.
Planetariums and hands-on museums were also great.
Cooking because of the measuring, counting, etc was always enjoyable for DD.
We did a lot of building with DD too. It was Gears! Gears! Gears!, marble runs, MagnaTiles etc.
We encouraged chess at a young age (5/6) and also played a lot of card-based games with DD.
If you have a daughter, we found the recommendations of books and toys/games from a Mighty Girl to be quite good, especially for the preschool to upper elementary years:
https://www.amightygirl.com/
DD started Math Olympiad in 4th grade as well as did a science-themed afterschool class focused on rocketry that same year. She continues to enjoy math and science many years later.
Games, books, and hands-on exploration helped tremendously, especially between the ages of 3 to 10 or so. Some math-focused workbooks for car or train trips were used in the summer but we tried to make math and science fun and seem natural in the younger years vs as an academic endeavor.