For those indoor days, Montessori climbing ladders can be a great choice. They're designed to be safe and encourage physical development, offering a fun way for toddlers to use their energy productively indoors. These climbing structures support motor skills and can be a fantastic addition to your play area. I found a variety here:
https://goodevas.com/en-gb/collections/montessori-climbing-ladders It’s a good way to keep playtime both fun and beneficial for their development!