MCDisc is a free online tool that allows you to create Minecraft Java Edition Resource Packs with custom Disc sounds and textures!
Editing the pack
Give your resource pack a name by pressing on "Minecraft Resource Pack". You can edit it to whatever you want, but make sure to pick something cool!
Edit your resource pack icon by clicking on the icon on the left of the resource pack name, you can decide to not do it, but it's pretty cool if you ask me.
Scroll through the discs and choose which one to change.
Editing a disc
Click on the disc image to change the textures (.png)
Click on "Not selected yet (.ogg)" to change the sound of the disc. Need to convert your file to .ogg? Use these services.
Download your pack
When you're done editing your discs, simply click on the Download button.