I have setup a Qube that I use for my video calls pretty much every day. Now it’s a bit annoying that on every boot of my laptop, I have to reconnect my microphone, speaker and camera. Is there a way to default connect these three devices on boot to a Qube? The Qube is also starting on boot - that part I already figured out 
You can attach your devices with the --persistent option.
https://www.qubes-os.org/doc/how-to-use-devices/
To attach a device, the qube must be running.
e.g. (in dom0)
$ qvm-device mic list
BACKEND:DEVID DESCRIPTION USED BY
dom0:mic Microphone
$ qvm-device mic attach --persistent VMNAME dom0:mic
$ qvm-device usb list
BACKEND:DEVID DESCRIPTION USED BY
sys-usb-dvm:2-12 XXXXXXX_Integrated_Webcam
$ qvm-device usb attach --persistent VMNAME sys-usb-dvm:2-12
edit:
the keywords you was looking for are: “attach device boot”
https://forum.qubes-os.org/t/any-way-to-auto-attach-sata-devices-to-vms-set-to-start-on-boot/14657
https://forum.qubes-os.org/t/solved-attach-more-than-one-device-during-boot-time/11883