As far as live foods go...
The super easy:
1) White worms (not a marine organism, but have a great profile and survived DAYS in the tank with no issues -and usually NEVER last that long in a tank anyway)
2) Baby brine. This is not my favorite food to feed, but it is easy to grow -so its on the list.
Easy:
3) Rotifers (easiest to use RG complete and harvest 1/3 every day even if you just dump them)
4) Nanno (phyto) can be used to feed tanks pod population as well as rotifers
5) Tigger pods. This is a weird one. I have a hard time growing them in a tank. However, if you simply drop a heater in a dark colored container in your yard they are like roaches. I used to feed live phyto, now I simply add a bit of BRS reef chili when I think about it. I have no idea what they are consuming -presumably whatever drops into the bucket and whatever bacteria is feeding on the stuff decaying in the bucket.
Medium:
Tsibe pods
Next tank I will probably end up doing rotifers, white worms, tigger pods, and mysid (the setup tanks for these are a bit complicated, but doable if set up right). Aside from Lapins great suggestions above also check out anything written by Paul B on this site!! Wealth of info.