If you want a simple first game then I'd vote for no durations. People who don't know the game will sometimes have a horrible time remembering when and when not to discard them and get their benefits.
I'd also avoid attacks that scale in multiples as multiplayer games can get ridiculous with them.
There are also some cards with choices that new players simply won't know what to do with and you should avoid them as well.
Hence I'd rule out the following:
Pawn, Swindler, Saboteur, Torturer, Tribute, Embargo, Haven, Lighthouse, Native Village, Ambassador, Fishing Village, Caravan, Pirate ship, Sea Hag, Merchant Ship, Outpost, Tactician, Wharf.
Here's some things that you probably want in your first game.
Terminal Draw:
Courtyard, Masquerade, Steward, Nobels, Ghost Ship
A Village:
Shanty Town, Mining Village, Nobels, Bazaar
Virtual Money and +buy (the latter being contained in the former here):
Secret Chamber, Steward, Baron, Bridge, Conspirator, Minion, Cutpurse, Navigator, Salvager, Bazaar, Treasury
An Attack:
Minion, Cutpurse, Ghost Ship
A cantrip:
Great Hall, Wishing Well, Mining Village, Upgrade, Pearl Diver, Bazaar, Treasury
Here's a possible suggestion:
Courtyard, Shanty Town, Wishing Well, Bridge, Nobels, Smugglers, Warehouse, Cutpurse, Salvager, Bazaar