You might search through Diskmaster to see if you can find sounds that would be suitable for your PC. They're all taken from the collections on Archive.org, so there are probably quite a few desktop theme collections to search through:
https://discmaster.textfiles.com/You can specify what types of files you're looking for, so for instance, looking for audio files with the name "minimize" brings up these:
https://discmaster.textfiles.com/search?q=minimize&family=audio===========================================
And now for story time! This is a story I read a long time ago on the internet somewhere, probably in an old forum, that I still think about from time to time. Back in the day, it was pretty common for users to change their sounds around to whatever we wanted, and along with the "95 Plus!" extra themes that came with Windows 95, you could surf around the internet and download packs that had different themes--usually movies, cartoons, etc.
This one particular user was a sports fan and really liked a certain basketball team (I've never followed this field, so I don't remember anything about which one it was). So naturally, they themed their desktop around said team, and even decided to set their shut down sound clip to a recording of their theme song, for funsies. This user then proceeded to
never shut their computer down again, as you did back in the day, because they didn't particularly care about preventative maintenance.
Naturally, after some time the PC went a little bonkers and needed maintenance, so they put in a call to whatever tech support they had a relationship with. The tech on the phone, as a natural first step, asked the user to restart the PC and see if that fixed the problem. Queue the theme song playing loudly while the shut down process began. Apparently, though, the shut down process will
refuse to complete until the sound clip has finished playing, and this theme song was a full 3:something minutes long, which meant that they were stuck on the phone while listening to a bombastic fight song playing through their speakers for more than three very slow minutes.
User was struck with waves of embarassment while saying, "I am
so, so sorry" to the tech on the phone, who was trying unsuccessfully to not laugh on the other end.