What commands are deprecated by systemd

The obvious ones - these are what systemctl replaces:

• service
• chkconfig on redhat and update-rc.d on debian, if a systemd unit has been written for the service.
• reboot, poweroff, halt, telinit.
• pm-suspend and friends have apparently gone away. As a cross-distro effort it's the sort of thing that systemd aims to accomplish; it's just interesting given the hooks and quirks that pm-utils supported, and I'm not aware of any fallout from systemd replacing it.

Also systemd-analyze provides a similar function to bootchart.

As pointed out by others, it probably makes more sense to enumerate the files provided by systemd, or the documentation. By doing so, I noticed one more obscure command, runlevel.

systemd only emulates runlevels, so runlevel is another of the legacy commands. Searching for an equivalent command turned up systemctl list-units --type target (note list-units only shows active units unless directed otherwise). The output is not as obvious, because targets tend to depend on other targets, and you can have multiple targets active at once, independent or overlapping.

However for now I can't think exactly when you would use the runlevel command. I have an impression it would be used interactively as a summary of the state of the init system. In which case, the better alternative would be systemctl status.

You could browse the man pages that systemd comes with. On my fedora 22 I see

$ rpm -ql systemd | grep -c man1
  32
$ rpm -ql systemd | grep -c man8
  111

32 man pages for commands like localectl, and 111 pages on features like systemd-timedated. Alternatively, look through apropos systemd.