I played a support OD before in a 5 carry draft because my team didn't know what they were doing. I got urn and basically became a walking fountain. He was good for zoning and offensive and defensive banish. Got scepter and would just ult as many as I could to mana burn. It was ok, not really super fun.

Lately I have been running a 5 position Mirana and absolutely wiping the floor with people. She is just amazing as a support. I know she is out of the meta currently because she isn't viewed as reliable. But we aren't playing against pro players. Just devastating when you land a 5s arrow on a mid or offlane. You basically just won the early game for that lane by being patient and setting up you core in lane.

My build has been tango, 2 branches, and 2 clarity. Use the remainder for whatever support items you need. Get sobi mask asap, into soul ring. Tranquils, and I get a naked void stone. With that combo you can pretty much arrow every time it is up. It is a great way to have site around a tower you want to take and scare them at the same time. The void stone is later made into a scythe late game. Nothing stronger than arrow into sheep. There is a ton of experience and patience needed to be good at Mirana support but she really is top tier after spamming her over my past 10 games.

Max arrow first because that is all you will be doing most of the time. If you land an arrow DO NOT use leap to get to them for more damage or you are basically signing your death warrant. After arrow, max Q. That os when you can start split and counter pushing. Your ult lets you always cover your team regardless of where you are. If someone gets caught out just use it. The cooldown isn't long enough to be stingy with it. But getting Q maxed mid game is how you get the scyth by 30 to 40 minutes so you are still a quality support for your end game fights.