The Debian port to the alpha architecture, currently not by-release as of 5.0 “Lenny”.
The Debian port to the ARM architecture, with 32 and 64 bit versions.
The Debian port to the AVR32 architecture, not supported as of 2010 or so…
https://web.archive.org/web/20130326061253/http://avr32.debian.net/
The Debian port to the PA-RISC architecture, currently not by-release as of 6.0 “Squeeze”.
The Debian port to the i386 architecture, being the first port of Debian released.
The Debian port to the IA-64 architecture, currently not by-release as of 7.0 “Wheezy”.
The Debian port to the m68k architecture, currently not by-release as of 4.0 “Etch”. Attempts are being made to revive this port up to by-release standards.
The Debian port to the MIPS architecture, with various endianness versions.
The Debian port to the PowerPC architecture, with various levels of bit support.
The Debian port to the “PowerPC SPE” architecture on certain IBM PPC processors.
The Debian port to the RISC-V architecture.
The Debian port to the SuperH 4 architecture.
The Debian ports to the SPARC architectures.