For the Rebel NetWinder, HP Armada and other devices having an ARMv4 processor, which is only capable of running the old ABI. Nevertheless it should work on newer CPUs.
For the OpenMoko FreeRunner and other devices using an ARMv4T processor. Uses the new ARM EABI and software floating point by default.
For almost all ARM NAS, devices based on the Marvell Orion and Marvell Kirkwood, Marvell Sheevaplug, Marvell OpenRD, Guruplug, Dreamplug, QNAP TS109/TS209/TS409/TS119/TS219/TS419, Buffalo Linkstation/Kurobox PRO, HP mv2120, HP iPAQ, Linksys NSLU2 and other devices using an ARMv5TE processor. Uses the new ARM EABI and software floating point by default.
For Nokia N800/N810, Smart Q7, OMAP2-based devices and other multimedia devices using an ARMv6 CPU and VFP. Uses the new ARM EABI and hardware floating point by default
For OMAP3-based devices(Beagleboard, IGEPv2, Devkit8000, AlwaysInnovating Touchbook, Nokia N900), OMAP4-based devices(Pandaboard), Freescale i.MX515-based devices(Efika MX, Babbage Board, Lange Board…) Marvell Dove/Armada, Nvidia Tegra2-based devices(Toshiba AC100, Toshiba Folio), ST-Ericsson NOVA A9500-based devices(Snowball) and other devices using an ARMv7-A processor. Uses the new ARM EABI and generic(not NEON) hardware floating point by default
The same as armv7a-unknown-linux-gnueabi, but this one uses hardfloat instead of softfp. Read more about it here: http://wiki.debian.org/ArmHardFloatPort
You can find them on your favourite mirror or clicking on the links above.