Debian follows the Debian Partition Manual available at https://www.debian.org/releases/jessie/amd64/apcs03.html.en and https://www.debian.org/releases/jessie/amd64/apcs02.html.en. Anything other than the standard partition scheme are my tested variants.
In Debian 9, these are are recommended minimum schemes and allocations scheme from Debian Manual. We often look into 2 forms: single root scheme or split scheme.
For single root scheme, it's plain simple: you need 3 partitions:
/boot
➟ 250 MiB ~ 1 GiB | ext2 filesystemswap
➟ 0 OR equal to RAM size/
➟ 150 MiB to rest of the disk | ext4 filesystem/boot
➟ 250 MiB ~ 1 GiB | ext2 filesystemswap
➟ 0 OR equal to RAM size/
➟ 250 MiB ~ 40% of disk OR 250GB | ext4 filesystem/home
➟ Remaining of the disk | ext4 filesystem/boot
➟ 250 MiB ~ 1 GiB | ext2 filesystemswap
➟ 0 OR equal to RAM size/
➟ 250 MiB ~ 40% of disk OR 250GB/tmp
➟ 25 MiB ~ 50 MiB/home
➟ Remaining of the disk/boot
➟ 250 MiB ~ 1 GiB | ext2 filesystemswap
➟ 0 OR equal to RAM size/
➟ 250 MiB ~ 40% of disk OR 250GB/tmp
➟ 25 MiB ~ 50 MiB/var
➟ 2 GiB ~ 3 Gib OR 100 GiB (depending on what you plan to do, e.g. libvirt takes a lot of space)/home
➟ Remaining of the diskThat's all about Partition Scheme for Debian operating system.