Let's see if I can widen this to 25 as other people have done...
1. Katun, Mirabilandia
2. Nemesis, Alton Towers
3. Helix, Liseberg
4. Vampire, La Ronde
5. Colossos, Heide Park
6. Shambhala, Port Aventura
7. Black Mamba, Phantasialand
8. Wodan, Europa Park
9. Behemoth, Canada's Wonderland
10. Expedition ge Force, Holiday Park
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11. Leviathan, Canada's Wonderland
12. Blue Fire, Europa Park
13. Troy, Toverland
14. Baron 1898, Efteling
15. Lynet, Farup Sommerland
16. Fluch von Novgorod, Hansa Park
17. Balder, Liseberg
18. Os Iris, Parc Asterix
19. DC Rivals Hypercoaster, WB Movie World
20. The Swarm, Thorpe Park
21. Lost Gravity, Walibi Holland
22. Dragon Khan, Port Aventura
23. Psyke Underground, Walibi Belgium
24. Anubis, Plopsaland
25. iSpeed, Mirabilandia
I've probably had more than one ride on most of the coasters in bold, but have only been to the park on one specific holiday during the coaster's operating life - as such, opinions subject to change. This is based on coasters rated 8 or higher on my spreadsheet, so it's quite possible I've forgotten one or two. I've also made the decision to remove Blackpool's Wild Mouse, which would probably have been top 20 material before it got spited.