Homebrew has the capability to add (and remove) multiple taps to your local installation with the `brew tap` and `brew untap` commands. Type `man brew` in your Terminal. The main repository [https://github.com/Homebrew/homebrew-core](https://github.com/Homebrew/homebrew-core), often called `homebrew/core`, is always built-in.
* [homebrew/apache](https://github.com/Homebrew/homebrew-apache): A tap for Apache modules, extending macOS's built-in Apache. These brews may require unconventional additional setup, as explained in the caveats.
You can be added as a maintainer for one of the Homebrew organization taps and aid the project! If you are interested please feel free to ask in an issue or pull request after submitting multiple high-quality pull requests. We want your help!
* [InstantClientTap/instantclient](https://github.com/InstantClientTap/homebrew-instantclient): A tap for Oracle Instant Client. The packages need to be downloaded manually.
* [besport/ocaml](https://github.com/besport/homebrew-ocaml): A tap for Ocaml libraries, though with caveats, it requires you install its customized ocaml formula. Perhaps a template for more work.
* [osx-cross/avr](https://github.com/osx-cross/homebrew-avr): GNU AVR toolchain (Libc, compilers and other tools for Atmel MCUs, useful for Arduino hackers and AVR programmers).