You could ask the school for a termly or yearly curriculum.
In addition to other comments here, being outdoors in nature, learning names of birds, plants, trees, animals, insects, getting those bug collecting kits, binoculars for looking at birds, watching the clouds, planting seeds on the windowsill and watching the life cycle, food growing, watching nature documentaries, talking about weather and climate change, recycling, etc..
It did help having an idea of the curriculum so as to focus on a few connected themes, though. E.g. zoo trips when they studied animal life cycles. Just googling the curriculum themes for your child's key stage might help.
Also for science, as they get older, science kits like basic circuits, magnets, automatons, robots.
It's impossible to do everything. I've done a lot of reading and nature activities, but fall short on art and music. The important thing is to foster a sense of curiosity and excitement, especially as school can be very boring.