First rainy half marathon: what to pack? What to do?

I've only had one rainy race, but it was a doozy - Boston 2018. From discussions before and after I learned a lot. 1. Bring something warmish to wear before the race that you toss before the gun goes off. A lot of people had old shoes, others wore plastic bags over their feet. The bags were slippery when dealing with the mudpit that was the Athlete's Village. People that had spare shoes were happy. I just figured my feet were going to get soaked on the walk to the start, so why bother. 2. Hat with visor is a necessity. Not having rain in my face made the downpour a lot more tolerable. 3. Temperature makes a huge difference. Rain and under 40 F requires more protection than rain over 40 degrees. Don't wear a rain jacket if it's over 45 or so. A garbage bag or light poncho will keep you warm enough. With a jacket you just sweat a lot. 4. Lots of vaseline - between your toes, any place that might rub like thighs, under arms, etc. 5. Clothes that fit close to your body will chafe less than looser clothes. 6. Most important - don't let yourself get psyched out by the possibility of a wet race. I saw a lot of runners get really upset and depressed about the forecast. They were so sure the day would be awful, it was, for them. I am a backpacker, so all day rain is not something new to me. I just laughed as the forecast kept getting worse and worse. Even though I had never run in those conditions (38 F, torrential rain, 25 mph headwinds) I was there to enjoy myself, so I did. I thanked all the volunteers and onlookers, high fived the kids, and ran my heart out. I ended up with a 10 minute PR.