RaikouRider: An interesting utility land for sure. It seems like it encourages playing on your turn which is nice. It seems quite easy to amass a fair amount of counters, and I feel like because of this it might be a little unfun for any graveyard based deck to play against.
slimytrout: A simple design (is it rare-worthy?). It rewards you for attacking which could be seen as crossing the Bifrost to invade enemy territory. Also bonus points/high five/shoulder tap for using Raid as well.
Ink-Treader: It's a nice design, but not very sexy. There's good flavor, but it doesn't scream to me as something that would be worth playing.
netn10: There's always something spicy about lands with no mana abilities. A mix of Eladamri's Vineyard and Manabarbs. It brings back mana burn in a way which is cool, but a part of me almost feels like it would be better for punishing people who spend the mana rather than if it's unused, but there's an appeal to both sides. I very much like this design.
jamblock: This feels very flavorful considering there are two colors (one for each river), Keranos already being the Storm god on theros and the synergy with Storm-style decks. This would generate a lot of mana with something like Grapeshot, and so the self-ping aspect definitely helps curb the huge potential this can offer. Plus if you somehow turn this land into a God creature, it untaps itself.
kwanyeegor-ii: Feels a bit weird that part of a tree doesn't produce green. A
Dramatic Entrance on a land is definitely powerful. The flipped side is nice? but probably a little too narrow a reward? You get four times more mana and an anthem to some specific types. I think that the reward should be a little more powerful/broad to show how important/relevant the World-Tree is to norse mythos.
Henlock: Another reference to the Niddhog, and one I like more than RaikouRider's. A little dissapointing that it itself isn't a Lair card, but it's having a 6/6 hexproof token as a reward for your pseudo Deathrite Shaman land is pretty nice, but it also feels like an underwhelming reward when you compare it to something like
Azor's Gateway/
Sanctum of the Sun.
Top 3:
1: netn10
2: jamblock
3: Henlock