[Brooks Orpik](https://en.wikipedia.org/wiki/Brooks_Orpik) playing for Washington Capitals won Stanley Cup in [2009](https://en.wikipedia.org/wiki/2009_Stanley_Cup_Finals) with Pittsburgh Penguins.

Vegas goaltender [Marc-André Fleury](https://en.wikipedia.org/wiki/Marc-Andr%C3%A9_Fleury) won three Stanley Cups - also with Penguins - in [2009](https://en.wikipedia.org/wiki/2009_Stanley_Cup_Finals), [2016](https://en.wikipedia.org/wiki/2016_Stanley_Cup_Finals) and [2017](https://en.wikipedia.org/wiki/2017_Stanley_Cup_Finals). 

Both Orpik and Fleury also played in [2008](https://en.wikipedia.org/wiki/2008_Stanley_Cup_Finals), where Penguins lost to Detroit Red Wings.

In the [2017 Stanley Cup Finals](https://en.wikipedia.org/wiki/2017_Stanley_Cup_Finals), [James Neal](https://en.wikipedia.org/wiki/James_Neal_(ice_hockey)) played for Nashville Predators, Predators lost the series to Penguins 2-4. He also currently plays for Vegas Golden Knights.

This should be all players with previous Stanley Cup final appearances from the rosters of the the two finalists according to sources below and also according to the Wikipedia article [2018 Stanley Cup Finals](https://en.wikipedia.org/wiki/2018_Stanley_Cup_Finals). (Here is link to the [current revision](https://en.wikipedia.org/w/index.php?title=2018_Stanley_Cup_Finals&action=history). Notice the column "Finals appearance" in the section [Team rosters](https://en.wikipedia.org/wiki/2018_Stanley_Cup_Finals#Team_rosters).)

 * [NHL Morning Skate: Stanley Cup Final Edition – May 27, 2018](https://media.nhl.com/public/news/12133?utm_source=morning-skate&utm_medium=twitter&sf88859652=1)
 * [Golden Knights leaning on Fleury, Neal heading into Stanley Cup Final](https://www.nhl.com/news/vegas-golden-knights-leaning-on-fleury-neal-heading-into-stanley-cup-final/c-298801796) 
 * [Ex-Penguins Brooks Orpik, Marc-Andre Fleury know Cup success](http://triblive.com/sports/penguins/13685912-74/ex-penguins-brooks-orpik-marc-andre-fleury-know-cup-success) 
 * [Brooks Orpik is only Capital with Stanley Cup finals experience: ‘A big role model’](https://www.washingtonpost.com/news/capitals-insider/wp/2018/05/26/brooks-orpik-is-only-capitals-player-with-stanley-cup-experience-hes-a-big-role-model/?utm_term=.8a37279bc976)