High Speed USB Drive
Use the USB stick to record automatically record dash cam footage while driving and footage when in Sentry mode. You'll need to format the drive. Read for instructions. Wall Connector (charger)
Wall chargers come in two colors (black/silver) and two cord lengths (8 ft/25 ft). Make sure to order the 25 ft length unless your charger will be located very close to your Tesla's charge port when parked.
All Weather Floor Mats
I think these are the nicest available on Amazon. They fit really well, look great, and make it very easy to keep the car clean. There are cheaper alternatives available on Amazon.
All Weather Trunk/Frunk Mats
Cup and Center Console Liner
Nomad Wireless Phone Charger
This is a really slick charger to support charging two phones wirelessly. Also includes the USB splitter cables so you can still use a hard drive or other USB accessories.
Center Console Wrap
The center console scratches incredibly easily. You can install a wrap to protect it, or some people just solve this by leaving the console open all the time.
FastTrak Flex Toll
Makes driving in express lanes and toll lanes easy in California. Available to purchase at retailers like Costco.
Rim touch up pen
If you accidentally curb your tires and scratch your rim, this touch up paint can help you make it hard to notice.
HomeLink Upgrade
Set up Tesla HomeLink to enable opening of garage doors.
Cup holder inserts
Helpful accessory that makes it easier to keep most cups/bottles stable in the cupholder.
Dragy
If you want a fun way to measure your car's performance, this accessory might be great for you!