Expansions have a poor reputation for a reason. Most add complexity without adding much genuine value, bolting extra rules onto a game that was already working fine. The five below are different. Each one solves a real weakness in its base game or adds a dimension the original was clearly missing, and all five are worth the money if you already own the core box.
If you’re still deciding on the base game itself, several of these are covered in our best strategy board games for adults guide. What follows assumes you already own the original and are wondering whether the expansion is worth adding.
Terraforming Mars: Prelude
Prelude solves the single biggest complaint about base Terraforming Mars: the slow opening turns before your engine actually starts producing anything meaningful. It adds a short setup phase where players choose from prelude cards that jump-start their tableau, cutting a noticeable chunk of dead time off the front of every game without changing the strategic identity of the base game at all.
For a game that already runs two to three hours, trimming twenty minutes of slow build-up off the start is a genuine improvement rather than an optional add-on, which is why most experienced players consider this close to essential.
Wingspan: European Expansion
The European Expansion adds eighty-one new birds along with a nectar resource type, giving the base game meaningfully more variety without disrupting the core engine-building loop that made Wingspan popular in the first place. New players can ignore it entirely and the game still works fine, but for anyone who’s played the base set repeatedly, the new bird pool keeps sessions feeling fresh.
It also adds a bonus card interaction that rewards players who mix birds from both the base game and the expansion, which encourages experimentation rather than simply defaulting to whichever set feels stronger.
Root: The Underworld Expansion
Root’s asymmetric faction design is what made it stand out among the titles in our military strategy board games guide, and the Underworld Expansion doubles down by adding two entirely new factions, the Lizard Cult and the Riverfolk Company, along with new map options and hirelings that any faction can recruit.
What makes this expansion stand out is that the new factions don’t just add more of the same mechanics with different names. Each plays with a genuinely different strategic identity, which keeps a group that’s already mastered the base factions from hitting a wall of repetition.
Brass: Birmingham Network Expansion
Brass: Birmingham didn’t obviously need an expansion given how tightly the base game is designed, but the network expansion adds new starting positions and industry tiles that meaningfully shift the opening strategy without touching the core canal-and-rail mechanics that made the original so respected. It’s a smaller addition than most on this list, but it extends a game that experienced players were already replaying dozens of times.
Spirit Island: Jagged Earth
Jagged Earth is less an expansion and more a second game bolted onto Spirit Island, adding eight new spirits, new adversaries, and a branch system that lets spirits specialise their powers in different directions as the game progresses. For a cooperative game already praised for its depth, this expansion roughly doubles the strategic possibilities available.
It’s a heavier addition than the others on this list, both in rules overhead and in price, so it’s best suited to groups who’ve already played through the base spirits enough times to want genuinely new strategic puzzles rather than more of the same.
Which Expansion to Buy First
If your base game feels like it’s starting to run dry after repeated plays, Wingspan’s European Expansion or Root’s Underworld Expansion will do the most to revive it. If you want a smaller, sharper fix for a specific pacing problem, Terraforming Mars: Prelude solves exactly that. And if you’ve genuinely mastered a base game and want something closer to a sequel, Spirit Island’s Jagged Earth is the deepest option here by a wide margin.
Splendor: Cities of Splendor
Cities of Splendor adds a genuinely new endgame objective layer to a base game that had started to feel solved for experienced groups. Players can now work toward city cards that reward specific combinations of development cards, giving a second scoring path alongside the standard fifteen-point race and encouraging strategies that the base game never quite supported.
It’s a smaller box than most on this list, both in price and rules overhead, which makes it one of the easiest expansion purchases to justify even for a group that only plays Splendor occasionally.
Azul: Summer Pavilion
Summer Pavilion functions closer to a standalone game sharing Azul’s drafting DNA than a traditional expansion, replacing the wall-building grid with a hexagonal star pattern and six colours instead of five. For groups who’ve played the original Azul dozens of times and can predict scoring outcomes almost on sight, the new geometry resets that intuition and forces genuinely fresh spatial planning.
It works well as a second Azul purchase rather than a strict upgrade, since many groups end up keeping both versions in rotation rather than replacing the original entirely.
How to Tell If an Expansion Is Worth Buying
Not every expansion earns a place on the shelf, and a few questions can save you from a wasted purchase. Ask whether it solves a genuine problem with the base game rather than just adding more content for its own sake. Ask whether your group has played the base game enough times to actually notice that problem. And ask whether the added rules overhead is proportional to what you’re getting back, since an expansion that doubles the rulebook for a marginal strategic gain rarely earns its keep at the table.
How We Chose These Expansions
Every expansion on this list had to solve a genuine problem with its base game or add a meaningfully new dimension, rather than simply padding out the box with more of the same content. We deliberately avoided expansions that exist mainly to sell more components, and we checked user discussion specifically for language like “essential” or “changes how the game plays” rather than relying on marketing copy from the publishers themselves.
We also aimed for a spread across different price points and commitment levels, from Terraforming Mars: Prelude, a relatively small and inexpensive fix for a specific pacing issue, through to Spirit Island: Jagged Earth, a much larger investment that effectively doubles the base game’s content.
Signs an Expansion Isn’t Worth It
Not every expansion earns a place on the shelf, and a few warning signs are worth watching for before buying. If an expansion mainly adds more of the same card types without introducing a genuinely new decision, it’s likely to feel like padding rather than an improvement. If the added rules overhead roughly doubles the teaching time without a proportional increase in strategic depth, that’s usually a sign the expansion is solving a problem your group never actually had.
It’s also worth checking whether an expansion is fully compatible with base-game-only players, since some expansions create enough of a power gap that mixing expanded and non-expanded players in the same session becomes lopsided. This matters particularly for groups where not everyone owns the same components, a situation our beginner’s guide to strategy board games touches on when discussing how to build a shared collection.
Terraforming Mars: Colonies
Colonies adds an interplanetary trade layer to the base game, letting players build trade fleets and establish colonies on nearby moons and asteroids for additional resource generation and scoring opportunities. It’s a heavier addition than Prelude, adding genuine new strategic considerations rather than just trimming an existing pacing issue, and it works well for groups who’ve played the base game enough that the standard strategies have started to feel predictable.
The expansion also introduces a new player count option through its colony leader mechanic, which gives experienced groups another lever to pull when the base game alone has started to feel solved.
Storage and Table Space Considerations
It’s worth thinking practically about storage and table space before buying, particularly for the larger expansions on this list. Spirit Island: Jagged Earth roughly doubles the base game’s component count, which means a genuinely bigger box on the shelf and a noticeably larger table footprint during play. Smaller expansions like Terraforming Mars: Prelude add almost nothing to storage requirements, which is worth factoring in if space is at a premium.
Frequently Asked Questions
Should a beginner buy the expansion alongside the base game?
Almost never. Learn the base game first, ideally across five or more sessions, before adding any expansion content. Our beginner’s guide to strategy board games covers the core titles worth mastering before expanding your collection.
Do expansions always increase the rules complexity?
Usually, but not always to the same degree. Terraforming Mars: Prelude actually reduces the time spent in a slow opening phase rather than adding meaningful new rules, which is part of why it’s considered close to essential rather than optional.
Is it worth buying an expansion as a gift on its own?
Only if you’re certain the recipient already owns and enjoys the base game. Otherwise, a standalone pick from our Christmas strategy games guide is a much safer bet.
Not sure which base game to start with before worrying about expansions? Our strategy board game finder can point you in the right direction.
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