This is not necessarily a complete list. We may add some, we may remove some.

init - Self-explanatory. We're using SysV-style.
biod - NFS client daemon
crond - for cron jobs
dhcpd - for handling DHCP
fingerd - interface for the finger command and protocol
ftpd - FTP server
httpd - HTTP server
inetd - network connection requests
lpd - line printer daemon for print spooling
nfsd - NFS server daemon
ntpd - netword time sync
sshd - SSH server
sendmail - SMTP daemon
swapper/sched - manages swapping
syslogd - handles logging
syncd - keeps file systems synched with system memory
vhand - release pages of memory for other processes
ypbind - NIS daemon, basically