Have a search on ebay for “Waterproof aluminium card wallet”
I bought one to carry bank card, some cash and medication, thought it would be junk but worth a £3 gamble. It’s actually pretty good, not submersible, but weather proof. The catch will pop open if you over fill it, I put an elastic band round it and the rubber helps to grip it in your pocket too.
House key on a lanyard, I don’t have a car so ride from home.
You can get small bags from Alpkit, (Fuel cell, Stem cell) to carry these bits on the bike.