Things that might be useful to a system administrator and which don’t come pre-installed on Gentoo.
curl denyhosts fail2ban linkx lynx nload screen
In order to install “denyhosts”, you’ll probably have to muck with application specific keywords. See USE flags (gentoo.org) or FAQ USE Flags (Gentoo Linux Wiki). Look for information on editing the “/etc/portage/package.keywords” file. The current version of denyhosts is tagged with “~x86” (indicating that it compiles, but has not been verified?).