I play a lot of 'weird' games according to my friends, mostly cause I have no desire for all these Tripe A shooters and all that.
Anyways Terraria is a classic, it's 2D Minecraft but much more focused on combat than survival and exploring.
Kenshi is very fun in my opinion, it's meant to be difficult but you have the freedom to play how you want. You can be one character and play it as a real time RPG or you have have a group of characters and play as a RTS. It's ugly and buggy but the gameplay makes up for it.
I'm just bringing this up cause of your profile picture but Yume Nikki is on Steam now.
House Flipper is pretty fun but repetitive. Pretty much you buy houses, decorate them, and sell them.
Stardew Valley is very fun and laid back and has multiplayer support. I never played over games like Harvest Moon before but people say it's very similar as you grow crops and raise animals to make money. You also get to know and befriend all the townsfolk, you can even marry one or marry a friend instead.
Planet Zoo is pretty fun, it's like a modern Zoo Tycoon but it can be pretty hard as fulfilling animal and guest needs are more complex than in Zoo Tycoon 1&2. But the customizing is very free and you can make some beautiful exhibits and buildings.
City Skylines is like a modern Simcity as well, but my profile with it is you have to manage traffic and that's something I just can't get down. But I enjoyed it a lot anyway with the few times I've played it.