Alright one more for #9, for this one I'll think of a fifth hint before posting it this evening. So far guesses that were wrong were Civilisation V and Zoo Tycoon, it's neither of those nor in those series. While I'm at it I might as well post third hints for #7 and #6 as well, but no new game yet.
10 - When you finally get every collectible, you get a reward that very much drives home that doing so was pretty pointless and not necessarily meant to be done. Guessed by Darashiva - The Legend of Zelda: Breath of the Wild
9 - This game for some reason, has a lot to do about llama's.
Hint 2: In this one, there's even a cheat that turns your advisors into llama's.
Hint 3: Llama's also roam the countryside, or alongside the highway.
Hint 4: There's also a vehicle driving mission where there's a big emergency because someone slipped on "llama dung".
Hint 5: Lastly, there's a reward building which is a tourist trap shaped like a brown shed with a big llama head. It's ugly, and I don't want to build it.
8 - This looks like a 3D game, which it mostly is, but the characters are actually 2D cardboard cutouts. This is especially visible in the victory ceremony where the perspective seems off. Guessed by Veknoid_Outcast - Mario Kart 64
7 - When you start your town, you, the player, only gets a warehouse and a quay, while the AI also gets four tiles of nice paving next to it while that actually should still take quite a while before that is unlocked. I was also quite jealous of that.
Hint 2: They also have a bigger boat which should actually take even longer to unlock. Two of them do anyway, but that's not necessarily an advantage because they are much slower.
Hint 3: What is funny though is that one of the AI players will get big, colonising new lands and creating a big city reaching the highest tier, while the other AI always remains stuck at mere settlers.
6 - In the original, building "buildings" could only be done by raising land and painting the sides wood or brick, but in this game you can finally build actual walls and roofs. A real game-changer.
Hint 2: Hold shift to raise them or place them on top of each other to create some height, and also press control to keep a new piece at the last placed piece's elevation.
Hint 3: This works with walls and roofs, but also with scenery pieces big and small and stalls. Except trees, those can only be on the ground.
5 - The only game to feature parts in the main perspective of the second game in this series, while all others feature a different perspective. Guessed by Veknoid_Outcast - The Legend of Zelda: Link's Awakening