There's also https://github.com/termux/proot-distro which may or may not count as containers depending on how you define the word but I think it does count
you can theoretically run a virtual machine like libriscv5 which doesn't require root.
or qemu doesn't require root as well. But qemu is blocked for my usecase. There is flatpak theoretically as well
There's also https://github.com/termux/proot-distro which may or may not count as containers depending on how you define the word but I think it does count