Ok so I'm skipping all the ones you've mentioned in recommandations (if you need tips to maximize your days, let me know). For the rest, I'll try to divide it into sub-sections:
Nordics:
Liseberg: Actually one of the top park in Europe. It's really integrated into the city, feels like a place where locals enjoy some time with their families. They have some really really good coasters (Balder, Helix), some excellent flat rides, their seasonal events are top notch (halloween & christmas, but in christmas they close Helix which is a shame).
Djurs Sommerland & Farup Sommerland: These two have seen a lot of investment lately and have some really good roller coasters, with *some* theming. I'm grouping them as IMO they come as a package, you'd do both. If you're a LEGO fan, you can also do Legoland Billund and visit the Lego house, then your Danish trip will be complete with Tivoli Gardens. You can even go further south and go to Hansa Park in Germany. I wouldn't recommend Heide Park though, I only liked 3 attractions there.
Tivoli Gardens & Grona Lund: I'm grouping these two as they have the same characteristics: A lot of charm (one in beautiful gardens, one by the side of the water), both parts of beautiful capital cities, a lot of history (both more than 100years old, Tivoli Gardens inspired Walt...). Grona Lund is a bit crazy, everything there is tightly packed and intertwined, it's a very unique experience
I've also had a lot of fun in Finnish parks, including a completely empty PowerPark with 14x Junker, but it's fairly far.
Benelux:
Walibi World: An excellent line-up of coasters (with
Untamed being among the very very best in Europe, but also Lost Gravity, Goliath and X-Press), a crazy Halloween event and it's looking to build even more RMCs!
Toverland: The park grew from an indoor playground to a fully fledged 'outdoors' theme park, with beautifully themed zones. Great Wing Coaster
Fenix, great boat ride, lots of fun rides. Also, it's ideally located between your Dutch parks and Phantasialand. Or you can visit my home and then:
Walibi Belgium and Plopsaland De Panne: The two parks for which I've had the longest time an AP (I have walked to Walibi before, having lived so close to it
![Face with tears of joy :joy: 😂](https://cdn.jsdelivr.net/joypixels/assets/7.0/png/unicode/64/1f602.png)
). Both have some gems but are not amazing. Walibi:
Kondaa, Challenge of Tuttankhamon (+ Popcorn Revenge, Psyké Underground, Tiki Waka and Pulsar). Plopsaland:
Ride to Happiness, Anubis, Heidi the Ride. For my wife, not much beats a front row nighttime ride on Ride to Happiness, with music banging in your ears. Except maybe Hagrid's at night)
(rest of) Europe:
Parc Astérix: The park is about to open
Toutatis, a multi-launch coaster that looks like it will be insane.
Oziris is a great ride, the theming overall in the park is honestly not bad, they have good rides (not just coasters) and shows, it includes some unique things (don't want to spoil too much). It's also close to Paris so easy to combine with other activities (DLP...). The negatives: the local crowds are from the bad suburbs of Paris and therefore guests behaviour can be shocking.
Gardaland: Right by the Garda lake (hence the name), thus very easy to combine with Verona, Sirmione and all other beauties of Nothern Italy, this park has a few gems like the beautiful dark-ride
I Corsari, a great Fuga da Atlantide (water attraction), a few very nice B&M coasters. Really good to squeeze in your dose of parks while visiting nearby things. You can also visit Movieland Studios, about 10 min from the park, but it doesn't warrant a full day imo. I recommend spending the evening in Lazise, by the water
Energylandia: Located between the beautiful Krakow and the tragic Auschwitz, this park is your Polish Thorpe Park. Lots of thrills (
Zadra, Hyperion, Abyssus, Formula, ....) the park is constantly building new roller coasters). I found the park to feel a bit "unfinished" when I went, as in you could see lots of wiring everywhere. Other than that, 17 roller coasters + 3 in construction ... Do I need to say more?
You also have
Futuroscope that has a very "old school EPCOT" feel (
@marni1971 ), the two parks in Madrid that you know about,
I could talk about many more like: Tripsdrill, Holiday Park & Movie Park Germany, some more parks in Germany, Italy, Belgium, France, Austria, Turkey,... But this is already a good place to start.