This looks really weak to me. Without the Reaction, it's strictly worse* than Dungeon at the same price, and the Reaction helps your opponents just as much as it helps you, so it doesn't really add much to its strength.
Wording suggestion, taking a page from Artificer: "You may gain a card costing up to
per differently named card revealed."
Wording suggestion to shorten the bottom part: "You may trash a card from your hand to gain a different card with up to the same cost." Taking a page from Swap. That said, Donald is changing effects like this that have to be on-buy to be "when you gain a card you bought" so as to make it so you trigger the effect after gaining the bought card instead of before.
Wording suggestion: "You may discard, in order, an Estate for +3 Cards, a Duchy for +$3, and/or a Victory card for +3 Actions."
The "from the __ pile" part is no longer necessary, you can just say "you may gain a Road." Non-Supply piles can now be gained without specifying the pile as long as they are called out by name (the "from its pile" part is still necessary for Swamp gaining Spirits because it doesn't call out a specific Spirit).
I know this used to be called Hunter but you changed the name because of Allies, but Tracker is also taken:
Donald X is avoiding while-in-play effects nowadays, so you could change this to "This turn, Attack cards you play don't affect other players" if you care about that sort of thing.
The general consensus is that Grand Market, which is weaker than this, is a $7.5 without the no-Coppers restriction, so this is too strong even without taking into account the ability to end the game more easily.
Plundering
2
Event
Gain a Spoils from the Spoils pile.
As with Outskirts, you don't need "from the Spoils pile."
Parting
3
Event
Flip your Journey Token over. If it is face-up, gain a card costing up to $5.
I know this is really nitpicky, but the official term is "
turn your Journey token over."
Buerocracy
5
Event
Move your Bureaucracy Token to another Supply pile. (When you gain a card from a pile with your Bureaucracy Token on it, put it onto your deck).
Setup: Each player puts their Bureaucracy Token on the Province pile.
The name of the Event is misspelled, while the name of the token is not (although token shouldn't be capitalized).
Improve
5
Event
Trash a card from your hand. Gain a card costing up to $3 more than it.
This name is taken:
Contest
6
Event
Gain a card of your choice from the Contest pile.
-
Setup: Make a Contestdeck out of 10 different unused Kingdom cards costing $5.
You left out the space between "Contest" and "deck" in the setup clause.
Isolation
Edict
When you gain a card, you may exile it and gain a Copper.
1. "Exile" should be capitalized.
2. More importantly, this can instantly empty the Copper pile and give a colossal amount of Coffers in combination with Guildhall. You should either say "when you gain a non-Copper card" or "when you gain a card other than with this."
Trade Agreement
Edict
When you shuffle your deck during the game, you may gain a Silver and shuffle it in.
I don't think "during the game" is necessary, unless that's there to specify that shuffling at game start doesn't count.
Monarchy
Edict
Once per turn, when you play an Action card, you may set it aside here to play it again. Trash it at the start of your cleanup phase.
This has tracking issues with Duration cards.
Spellcasters & Spells
When a card with the Spellcaster type is in the supply, 3 Spells are chosen at random and put next to the Supply. Spells are effects similar to Events, which never go into your deck, but which you can buy in your buy phase. Each player gets 5 Spell Tokens in their color. When you buy a Spell, you put one of your tokens on the Spell you bought. That Spell is now "prepared". The only way to actually perform what a Spell does is when a Spellcaster card tells you to „cast a Spell“. By casting a Spell, you do what it says, then remove your token from the Spell. Naturally, you can have up to five Spells prepared.
Can you have multiple of the same Spell prepared? I assume so since you have 5 Spell tokens but there are only 3 Spells.
Grimoire
4
Treasure – Spellcaster
+$1, +1 Buy; When you play this, you may cast a Spell. You may discard a card, for +$1.
Treasures no longer need "when you play this."
As with Plundering and Outskirts, no "from the Spoils pile" necessary.
This needs to reveal the discarded cards. See Shepherd.
"But never less than
" isn't necessary, cards automatically can't have negative costs.
