Package

"Packages" are a small group of cards that interact heavily with each other can be run in various deck types within an archetype without much of a penalty.

Especially cards that tutor enable these two-card combinations that can be run regardless of the actual deck. Usually, you want to have full set of what you are tutoring for and 2-3 cards of the card that fetches the card. The reason why you might want to run 2 copies instead of 3 of the tutorer is that once you have drawn / tutored all the copies of the card you want to fetch further copies of the tutorer become less effective as they have nothing to fetch and won't gain you card advantage off them anymore.

Harpoon
The main gist of this package is that you attach Harpoon to an early unit to get free Mermaids. This package pushes you towards running few or no other fishes besides Mermaids. Given this isn't much of a cost and that both of the cards neutral, this package is widely utilized in aggressive decks regardless of affinity.

Baaaked
Baaaked Bun Broker can tutor up any food card so as long as you run only a single type of food card, it can be used to consistently pull out that card from your deck.

Festival
Winter Festival is a finisher for swarm decks. This package is especially useful for Buluc token decks even if it has to pay the 1 tick penalty for Festival.

Honeypot
Honeypot Ant Brew is a important piece for its combo decks.

Vanilla
This package synergizes with Return shell as Clattering Skeletons have empty text boxes.

Architect
Master Architect can tutor for places so it's especially useful decks that are very much reliant on any given place. The function of places vary wildly so it's especially easy to make the tutoring consistent here as it's unlikely a deck would like to utilize multiple places. An exception to this would be Dino Brew.

Vineyard, Spire, GCP
Vineyard of Desolation, Spire of Edenhold, and Galactic Command Post are crucial pieces for their decks that can act as finishers.

Starter Kit
Starter Magic Kit is an extremely powerful card that fetch up to two copies of a specific card. One such piece is Frozen Fish and this is utilized by Ashgerdy Actions deck. Another very powerful one that increases consistency of big combo plays is fetching copies of The Rich Get Richer.

Scaling
The idea of scaling is to cast it repeatably as its power increases with each cast. Obviously then the plan is to either recur or copy these cards. In spirit you have Scavenger Crab to recur Absolute Scaling and Soul Harvester Xil to copy the crab and/or Spellweaver. In mind, Temporal Research is a way to get off Spellweaver's summon trigger.

Staff
With this you are also expected to be playing Vriktik since the ghoul synergizes so well with staff.