Multiple ISOs with Ventoy
Ventoy allows you to boot of multiple different ISOs from a single USB drive. Either download it directly from https://github.com/ventoy/Ventoy/releases and read the documentation about how it works. Or follow my guide.
Linux
Before we start we need to install the exfat tools.
sudo apt update && sudo apt install exfatprogs
Determine the latest version (everything in one line).
version=$(curl -Ls -o /dev/null -w %{url_effective} https://github.com/ventoy/Ventoy/releases/latest/download 2>&1 | grep -Po [0-9]+\.[0-9]+\.[0-9]+)
Download the application (everything in one line).
cd ~/ && wget https://github.com/ventoy/Ventoy/releases/download/v$version/ventoy-$version-linux.tar.gz
Untar the the file you downloaded and enter that catalog.
tar -xvf ventoy-$version-linux.tar.gz && cd ventoy-$version
Run ./VentoyGUI.x86_64
Pick your USB stick in the list and click "Install"
Now you should have a mounted USB drive called Ventoy. Just copy as many ISO files as you want to the USB drive and they will show up in Ventoys boot menu.
Windows
Open Powershell and paste the commands below.
Get the URL to the for the latest release (everything in one line).
$result = (((Invoke-Webrequest https://github.com/ventoy/Ventoy/releases/latest -UseBasicParsing).Links | Where-Object {$_.href -like "*windows*"} ) | Select-Object href).href
Download the application (everything in one line).
Invoke-Webrequest -Uri https://github.com/$result -Outfile ventoy.zip
Extract the contents of the file, enter the catalog and run the application (everything in one line).
$version = $result.Substring(34,6); Expand-Archive -Path ventoy.zip -DestinationPath .; cd ventoy-"$version"; .\Ventoy2Disk.exe
If you get a popup saying
Do you want to allow this app form an unknown publisher to make changes to your deive?
Click Yes.
Select your USB drive and click Install. When it's done, just copy as many ISO files as you want to the USB drive and they will show up in Ventoys boot menu.