Some of my friends hate walking in the rain. Thank goodness for friends who have dogs. They have to go out so I tag along with them. I love the rain! Even if you're not out for very long, you can still get some good photos if you look closely enough. You will get wet through and mud up to your armpits but who cares!?
Red berries with raindrops are a particular favourite of mine, unless it's windy and they won't stop still.
I also love the red, orange, yellow autumnal leaves against the green ones, especially in the rain as they always appear more vibrant.
I don't like to over complicate things. I just think of KISS. Keep it simple stupid!