I know about the obvious stuff like a bright vest, blinking rear light and wearing light colored clothes but is there anything else that I need for when nightfall hits?
Get retroreflectors. White pointing forward, red pointing back. You won't always realize when a light craps out, it's best to have passive backups. Get amber-colored retroreflectors that you can put between the spokes so you have sideways visibility. You can also buy reflective tape and wrap it around the frame.
I recommend clear safety glasses. Especially if you live someplace dry. You don't want dust or insects in your eyes. I hit a palo verde beetle once and it almost knocked my glasses off my face.
Impressive! I struggle to get as far as a phylum or even kingdom identification in the moment something smacks my safety glasses. But looking at a picture of a palo verde beetle I can see how that would be unambiguous.
A lot of crashes are side impacts. So reflective frame tape or lights in spokes can help with side visibility. Some lights throw a little light to the side for this purpose as well.
As a commuter, a big upgrade for me was getting a peircing loud bike horn. Despite having multiple bright lights and high-vis, I still have multiple close calls a week with cars not looking before turning. Having a way to get a driver's attention without needing to rely on them even looking at all has been a huge benefit.
Additionally, this might be a controversial opinion, but I've found the wearing high-vis clothing often makes the issue worse. As a general rule, I try to select high-vis clothing that makes me look more like a motorcycle than a pedestrian. For example, I wear a reflective helmet and neon gloves, but not vests or shirts. When a driver waiting to emerge sees me, I want them to think "rapidly approaching vehicle" and not "slow moving pedestrian".
I use my bike like a car, and I live in a rural area. I regularly ride 20-30mph to fit in with traffic, so my experience may differ from yours if you ride in a slower, more urban environment.
I've been thinking about getting a horn. What kind of horn do you recommend? Anything that's electric and rechargeable? Or completely mechanical in nature?
I've been using the Hornit dB140, which has two modes. One is a loud peircing chirp sound, and the other is a much less loud sound resembling a car horn. I personally leave it on the peircing mode. The battery has lasted several months with regular use, so recharging isn't much of a concern.
The trigger is separate from the horn unit, which allows me to put it somewhere that I can hit the brakes and the horn at the same time.
I've been really happy with it, but I also haven't tried any alternatives to compare to.
Front and rear lights, obviously. You can get lights that offer side visibility and get a front light with a cut off lens so you aren't blinding oncoming peoole.
You can get vests or jackets that are basically one big reflector. The brand proviz makes a ton of options, but you can find them cheaper. I had one from a brand off Amazon and had peoole come up to me to ask about it because it was so visible.
Ankle reflective bands are one of the best types of reflectors you can get.
Tires with reflective sidewalls are awesome.
If riding during dusk or dawn, wear high viz with reflective elements. High viz colours alone aren't very visible in the dark or by vehicle headlights at night.
Make sure you have enough battery capacity to power your lights until your destination or use a dynamo and have a headtorch with you for backup. Your lights failing in the middle of nowhere on a cloudy night is no fun!
Go big on reflective clothing. Rather than having small reflective patches on your clothes or bike, you can get jackets where the whole garment is made of reflective fabric. When a car's headlights hit you that jacket will light up like the sun.
Studies have shown that blinking lights improve reaction time to bikes on the road. The most common issue is determining the distance to the bike. This effect is more pronounced during night.
That's why I use my bike lights all the time set to blink with a multi-second on phase. It makes me more noticeable and easy to estimate distance.
Also cars do have blinking lights these days. The newer car models like to blink the center brake light for a second before going static. Motorbikes have also long had rear blinking and "breathing" front light.