What is the best waterproof sealant? Outdoor use. Spray and brush.

For painted stepping stones; touching up paint on tin metal garden decor; painting a bird bath (so it would have to be non-toxic); painting bird houses that are just decorative (non bird use), metal baskets, etc. I've used PYM II spray - fast drying, acid free, inkjet print safe, water repellant polymer clay safe, light fast. It works great but it's a spray and now I can't find it in my stores. I really need something that probably is applied with a brush because some of my projects will be fairly large. I'm also going to paint an old wooden bench. Maybe I need more than one kind for the various projects. I used the PYM on stepping stones and it was amazing, they haven't faded in 3 years and I used acrylic paint to paint them. Thanks so much.