The /dev directory will be filled with files and directories, but to understand it you need to know the naming scheme (which differs a bit between Linux distributions), some key ones are:
/sda0 – Disk / Storage Devices
/nvme0 – NVM / Storage Devices
/ttys0 – Serial Ports
/psaux – PS-2 Port
(port number)
nvme – non-volatile memory express (https://en.wikipedia.org/wiki/NVM_Express)
/dsp0 – Audio Device
dsp – Digital Signal Processor
(Partition number)
/js0 – Joy Stick
Rather than tell you all of them, you know what they are now so you can look up the ones you need to know about