NCJbT5LPSD This is my favorite Seed so far. There are allot of flat areas in the mountain valley's close to Moder that are surrounded by mountains. I have buildt a spot NNW of Bonemass boss that has a swamp near by(SSW) with a spot of Plains surrounded by Black Forrest and Meadows with a small river that runs west and east. Great spot to grow any thing you need.
https://valheim-map.world/?seed=NCJbT5LPSD&offset=1225%2C268&zoom=0.109&view=0&ver=0.207.20

How bout mountain top/side overlooking a small width of black forest and plains meeting which then has some Ashlands touching from and moving towards the horizan Ashlands and water with the haze of red

Scenic area: End of the world Ashlands, in virtually any seed. You can literally breathe in the Ragnarok.

A very subjective question, no seed per se is the most scenic, its just an individual spot. Just have to go out and explore really.

It all depends on what you want in a scenic location. I image based on how the game generates that most seeds could provide what you want, you just have to go out there and find it.

Me? I'm a sucker for a small flat meadow looking out over the water with a mountain backdropping it. I like some natural verticality to an area since raising the ground has limitations.

The best way to find these seeds is using the seed generator. I found some pretty cool seeds using that website/tool. I don't remember those seeds as they were random or I would happily share them. Google Valheim Seed Generator and you'll be able to find the best ones.