Good list you made, but didn't Bernie Parent start with Boston?
And do you really want to claim Ron Low? He was a popular name in the "Worst Goalie Ever" thread a while back...
Anyway, as an Oilers' fan, where should I start? There are almost too many to name... the wonder is that the franchise managed to hold onto some good players before the free-agency era:
Bengt Gustafsson - should have been an Oiler from 1979, but the League screwed the team and they lost their claim on him. Sather was pissed. Went on to have around four PPG-seasons for the League's #1 defensive team (Washington). But he should have played with Gretzky and Kurri.
Martin Gelinas - 4 seasons as a young Messier-understudy (won the Cup in '90). After leaving, scored 540 more points and played 14 more seasons, including three further runs to the Finals.
Adam Graves - Oilers got absolutely nothing in return for a 23-year-old winger who'd go on to have four 30+ goal seasons (including a 52-goal season) for the Rangers, and 10-playoff goals on the way to the '94 Cup.
I dunno if
Jeff Beukeboom counts because he was already fairly well-known in Edmonton, but he left at age 26 to New York and went on to have seven solid seasons there, including the '94 Cup (during which run he went +17).
Martin Rucinsky - got in all of 2 games with the Oil before leaving for Quebec/Colorado, Montreal, Dallas, New York, St. Louis, and Vancouver, piling up almost 1000 games and 612 points.
Jason Arnott - Four-and-a-half decent seasons in Edmonton (including runner-up for the Calder) before leaving for Jersey, Dallas, and Nashville. 317 goals after leaving Edmonton at age 23. Oh yeah, and 20 points and a Cup in the 2000 playoffs.
Miroslav Satan - After 2 decent seasons in Edmonton, he went to Buffalo and the Island and put up some numbers. 35 goals for Edmonton; 328 goals after leaving Edmonton.
Ray Whitney - Sure, he'd already put in 4+ seasons with the Sharks, but the Oilers had him for... 9 games. They let him for nothing (on waivers). So, yes, the Oilers let a 1000+ point scorer, aged 25, go for nothing.
Mike Comrie - Okay, he was kind of a dick, but he did score 60 points at age 21. The Oilers let him go at age 22 for two guys who essentially never played for them; i.e., for nothing.
Andrew Cogliano - Left aged 23 after four point-declining seasons. Has now played 7 seasons and counting for Anaheim without missing a single game.
Devan Dubnyk - Three-and-a-half seasons for Edmonton before being traded to Nashville. Has made a home in Minnesota, with All Star nods since.
Justin Schultz - One of the worst-performing Oilers ever, Schultz nevertheless went to Pittsburgh, where he promptly became a top-four Dman, put up a 50+ point season, and won two Stanley Cups.
There are others I could have mentioned (like Dan Cleary, Raffi Torres, etc.) but this thread had depressed me enough.