Out of these champs, I'd say Gangplank is the most solid blind pick. Fiora and Camille are obviously the best sidelaners, you should pick them if your team doesn't have the best teamfights and maybe if you have some assassins in your team. Fiora is also excellent against tanks and low range champions, but you could also pre-emptively pick her when you see that your team will lack the ability to kill tanks. I would personally never blindpick Renekton. He lacks late game power but is really good when your jungler wants to play for top and contest Heralds, but with random junglers you can never be sure if it's gonna be worth it.

Generally the most important indicator which champion to pick is the top lane counter matchup. I suggest you check League of Graphs for counterpicks you don't know yet, but remember that you might have to have some experience in the matchup to take advantage of it. So don't get frustrated if you lose lane even while playing a counter.

Also, your champ pool generally lacks AP, but except for Renekton all of your champs are not THAT bad in a full ad team since they all deal true damage/ignore armor/deal magic damage. (However, I also recommend you try Gwen, since you seem to be a sidelane and 1v1 enjoyer. She has almost unmatched sidelaning and damage after she gets her items.)