Going to go for a bit of positivity. Post card (shaped things) that you really like.
Abundance: If you don't play it smart it's basically a workshop (early game gives you $3 after an Action, late game you arbitrarily buy Actions to activate it), but given its clear power it really encourages you to find strategies to make it count, such as by stacking. Sometimes they're no brainers (e.g. when Supplies is on the board) but generally it's more interesting especially considering you can trigger it before you really want to.
Witch's Hut: I initially thought the Attack was just thrown in as compensation for drawing the cards dead, because discarding 2 actions is such a high cost, right? Turns out there are lots of ways to consistently trigger the Attack in a well thought out strategy and it's fun to get there. Powerful with Big Money but the attack is too tantalising to resist so games with Witch's Hut usually end up interesting.
Cauldron: Similar to the above, I like the effort you need to put in to curse with this, either by lining up Cauldrons or gaining Actions at other times during your turn. It's really rewarding to pull off.
Grotto: Did Donald X learn nothing from the clunkiness of Research? This card is clearly worse than Cellar, right? Turns out, there's a really interesting design space in making cards miss the reshuffle. A really good "teacher card".
Stowaway: Lots of good ways to make use of its effect, even in games where it's the only Duration. i always like seeing it on the board, but it doesn't feel too powerful.
Replace: Especially compared to the card it... replaced (Saboteur is best forgotten). Just the perfect card for the likely first expansion people buy - it's Remodel, but has a few interesting tricks up it's sleeve. In playing with it, you end up realising more about what good old Remodel from the base set can do.
War Chest: My other favourite of the direct replacements. Amazing how such a simple tweak on the same mechanic can go from a card you regret buying to something very fun as you try to determine what card it is your opponent really wants. Really good non-attack interactivity.
Magnate: Other strengths of the replacements keep coming to mind. This card has all the fun of Counting House and Coppersmith in terms of seeming like it can be super powerful, but actually taking a bit of work to make work. But it feels far less luck based. A card where being situational feels very intentional and I want to see more like it. Also perfect for the theme of Prosperity.