Well many would add LT and pass rushers
I wouldn't, personally. Again, it's not that you want to trade him, but it doesn't hurt to listen when the phone rings.
LT and Pass rusher are key positions, but the difference between the best 2-3 LTs in the league or the best 2-3 pass rushers in the league and a solid, above average guy is not going to change the team record that much. One LT gives up 1-2 sacks per season and the other guy maybe gives up 4-6 sacks over 17 games; one guy gets 12-17 sacks while the other guy gets maybe 9-10 sacks. I can't imagine it changing the team's record much when the above average player is now surrounded by 2-3 other quality starters from the trade.
On the other hand, it's very hard to find even an average, competent NFL QB. That's why teams will pay an above average QB top money. It's not because they think he's elite but because the drop-off can cost them an entire season or more.
I certainly wouldn't trade Parsons or Lamb for say a 1 and a 2. I'm not thinking I'd even trade Parsons for two first round picks, not even from a crappy team, but I'd answer the phone just in case someone offered me 3 first rounders or 2 first rounders and a young, good starter at a position of need. Then I'd have to consider it. Of course, no one is going to offer that for Parsons.