Lots of kinds of anemones... Aiptasia and Majano for instance, won't die no matter what you do... some are quite sensitive. Rock flower or Mini Carpet anemones are common in reefs, and should basically be treated as an LPS coral might be.
I keep rainbow bubble tips in my reef, but I've got a large area dedicated to them. Remember, Anemones are mobile, and if they decide to move, there is very little you can do about it. Also, certain species get BIG, and sometimes, they get big FAST. I started with one small example. Now I have four, and small is not an accurate descriptor for any of them.
Stable water quality, no ammonia, no nitrite, very low nitrates, appropriate lighting and water flow for the species you're wanting to keep.