Pre-Built and Crosstool-ng

A few developers or companies offer pre-built toolchains
Unfortunately, the list is very volatile
Refer to elinux for a "current" list
https://elinux.org/Toolchains

Another option is crosstool-ng
Much more difficult than the original "crosstool"
Kconfig based
Reported to be reliable

For bare-metal (or kernel, or bootloader), distributions help
A suitable arm-none-eabi-gcc is usually packaged
Check your distribution for details

Please note the naming: "arm-none-eabi"
The first word is the CPU family
The second word is the host operating system
The later (optional) words are variants
We'll talk about ARM and EABI later on