I would assume that the usual rules apply. Combining them with the fact that the M3 MacBook Air can only drive two external displays when the lid is closed (freeing up the signal that would otherwise drive the built-in screen),
- You could use a "plain" USB-C dock to attach one display.
- You could use a Thunderbolt dock to attach two displays (when the M3 MacBook Air's lid was closed).
Either could give you multiple USB-A or USB-C (USB) ports for attaching USB accessories. A Thunderbolt dock could give you a Thunderbolt daisy-chaining port (or, in some cases, downstream Thunderbolt hub ports) which would support an external Thunderbolt 3 SSD.
You can find a lot of "plain" USB-C docks on Amazon. Other World Computing, SonnetTech, and CalDigit are all long-time vendors of higher-end Thunderbolt docks.
https://www.amazon.com/s?k=USB-C+dock
https://eshop.macsales.com/
https://www.sonnettech.com/home.html
https://www.caldigit.com/
Two examples (for illustration):
Other World Computing – USB-C Travel Dock E
A small, portable dock that gives you a HDMI port, two USB-A ports, a SD card reader, a Gigabit Ethernet port, and a place to plug in a USB-C cable from your power adapter (this port is just for plugging in power). Small enough to carry on a trip. There's a version that's $10 cheaper if you don't want the Gigabit Ethernet port.
Other World Computing – 14 Port Thunderbolt Dock
A large, wall-powered dock suitable for leaving on your desk. Has a Mini DisplayPort, and a daisy-chaining port that could support a USB-C display adapter. Also has card readers, five USB-A ports, a Gigabit Ethernet port, and audio output ports. This is just one of several full-size OWC docks, and they have plenty of competition from SonnetTech and CalDigit, so you're probably looking at a choice of close to 10 full-size Thunderbolt docks between the three.