Now I'm wondering if my board supports one. I think it'd be cool if my big fancy custom cooling loop gaming build sounded like it's from the early 90s.
Most boards still do. I have a couple x570 boards lying around that do, and my friend just got an x670e board that has one. They all have the setting in the BIOS for the POST beep as well, and you can set it up in your OS to beep at a specific frequency/duration for notifications.
Some motherboards have a tiny piezoelectric speaker soldered on, which replaced the larger speakers that used to be used. It's becoming less and less common though.
I hate it with a passion. The manual doesn't list that the CPU led and MEM led are lit when the +5V rail is too low from too much load on it from the USB devices.
though thinking about it I should probably figure out WHY that's a problem
Yeah the LEDs can be confusing. I like the fancy systems that have an eight-segment LED display (those basic ones that can show numbers and some letters) that show an error code. My work PC (a Lenovo ThinkStation) has the error code display on the front of the PC so you don't even have to open it to determine the issue.