Sister Slots: Every UK Slot Family, Compared and Verified
Most popular UK slots aren’t one game — they’re families. Sequels, jackpot editions, Megaways conversions and quiet reskins, often with different RTPs hiding behind the same artwork. Sister Slots documents every game in each family side by side, with figures checked against the providers’ own published data, so you know exactly which version you’re spinning.
What are sister slots?
“Sister slots” means two different things in the UK, and it’s worth knowing which one you’re looking for:
1. Games in the same family. When a slot becomes a hit, its studio builds on it — Rainbow Riches has spawned more than a dozen official versions, Big Bass Bonanza is a fleet of sequels, and Book of Dead sits inside Play’n GO’s wider Rich Wilde series. These sister games often share artwork and features but differ in RTP, volatility and max win. That’s what this site documents.
2. Casinos under the same owner. “Sister sites” are casino brands run by one operator on a shared licence. That’s a different topic — if that’s what you’re after, the UK Gambling Commission’s public register lists every licensed operator and the domains on each licence.
Every guide on Sister Slots covers meaning #1: the complete, verified family tree of a specific game — including the fake sequels and lookalikes that don’t actually exist.
How we verify every figure
Slot data on the web is a mess of copied errors. Our approach is simple: every RTP, max win and release date is checked against the provider’s own published material — and where the provider’s current figure contradicts what independent reviewers report, we show both numbers and explain the discrepancy rather than picking one. Each guide carries the date its figures were last checked, and our editorial policy explains how we research, correct and fund the site.
Most popular slot series
Rainbow Riches 25+ official sister slots, from Freespins to Megaways. 
Big Bass Bonanza The fleet of sequels that took over UK casino lobbies. 
Fishin' Frenzy A decade of the catch that started the UK's fishing-slot wave. 
Starburst The real family, and the sequels that don't actually exist. 
Book of Ra The Novomatic line that invented the book-slot genre. 
Megaways The mechanic that rewired UK casinos, game by game. 
Mega Moolah The full jackpot network behind the record-breaking wins. 
Gates of Olympus Zeus and every spin-off Pragmatic built after it.Featured Games
Explore individual game pages covering provider relationships, official families, shared themes and useful alternatives.
Rainbow Riches The Light & Wonder classic, with Irish imagery and a large official game family. 
Big Bass Bonanza Pragmatic Play's fishing hit and the starting point for a long-running series. 
Book of Dead Play'n GO's Egyptian adventure and one of the best-known Rich Wilde games. 
Gates of Olympus A Zeus-themed Pragmatic Play title with plenty of related mythology slots. 
Wolf Gold A wildlife-themed Pragmatic Play game surrounded by wolves, jackpots and western alternatives. 
Crabby's Gold 2 A Play'n GO pirate slot for comparing treasure hunts and seafaring games. 
Everybody's Jackpot A Playtech fantasy slot with jackpot-led alternatives from the same provider family. 
Donut City A colourful KA Gaming title for exploring food-themed and light-hearted alternatives. Most recent slot guides
- Slots Like Book of Oz: Four Games and the Sequel That Dropped the Name
- Slots Like Berryburst: The Pair That Launched NetEnt's MAX Experiment
- Slots Like Avalon: Every Grail Game From 2006 to the 2025 Revival
- Slots Like 9k Yeti: Every Real 4ThePlayer Game, Up to 90,000x
- Slots Like Wild West Gold: The Trilogy Pragmatic Actually Counts
- Slots Like Twin Spin: Five Official Games, One Quietly Delisted
- Guns N' Roses Slot: What Really Happened to the NetEnt Rocks Trilogy
- Slots Like Pirates' Plenty: Four Voyages, Every Map Unlocked
Latest guides
- Slots Like Book of Oz: Four Games and the Sequel That Dropped the Name
- Slots Like Berryburst: The Pair That Launched NetEnt’s MAX Experiment
- Slots Like Avalon: Every Grail Game From 2006 to the 2025 Revival
- Slots Like 9k Yeti: Every Real 4ThePlayer Game, Up to 90,000x
- Slots Like Wild West Gold: The Trilogy Pragmatic Actually Counts
- Slots Like Twin Spin: Five Official Games, One Quietly Delisted
Who writes Sister Slots
Every guide is written and maintained by Paul Miller, our Slots Editor — he researches slot-game families, provider histories, mechanics and published game data, checking material claims against developer pages, game sheets, official announcements and relevant public records, and maintains the site’s corrections and update process. Every page shows when its figures were last verified.
FAQs
What is a sister slot?
A sister slot is another game in the same official family — a sequel, jackpot edition or same-engine spin-off of an original title, made by the same studio. Sister games usually share a theme but often differ in RTP, volatility and max win.
Are sister slots the same as sister sites?
No. Sister slots are related games; sister sites are casino brands owned by one operator on a shared UK Gambling Commission licence. This site covers the games.
Why do versions of the same slot have different RTPs?
Studios often release several maths models of one game, and some publish updated figures years after launch. Our guides list each version’s published RTP and flag any conflicts between the provider’s current figure and independent test data.
How often are the guides updated?
New families are added weekly and every guide displays the date its figures were last checked against provider data.
Start here, by the kind of player you are
Not sure which guide to open first? Four common starting points, each linking to a page already live on this site:
| You are… | Start here | Why |
|---|---|---|
| A jackpot chaser | Mega Moolah | The full progressive network explained — how the pots pool, and every game wired into it |
| A low-volatility player | Starburst | The gentlest, most frequent-paying classic on the site — a good low-volatility starting point |
| Here for the nostalgia | Rainbow Riches | The pub-and-arcade original that built the UK's biggest slot franchise |
| Learning how slots actually work | Slot Features & Mechanics | Plain-English explainers for every mechanic referenced across our family guides |