In no particular order, they are...
Looks like a casual Pokemon meets Animal crossing with Harvest moon elements type of game, sounds perfect to me. I really love the cute and quirky art style of Ooblets, that's something that always really stands out to me, and I'm psyched to see more and more developers experimenting with different styles. I'm super excited for this game :D
2. Mineko's Night Market
'A whimsical adventure/simulation game' set on a Japanese island overrun with cats, sounds too amazing to be real, but it's happening you guys. More beautiful art to be seen, and the promise of some unique and memorable adventures exploring the island and attending the weekly night market.
Mineko's Night Market Trailer:
Play as the old (and adorable) witch of the woods in this beautiful crafting adventure game, collecting ingredients to brew spells in a land of fairytales and fables. Enjoy even more beautiful art and exploration as a witch with magic abilities. 2018 is shaping up to be the best year ever for cool games. :0...
4. Knights on Bikes
A HAND PAINTED ACTION ADVETURE GAME, 2 TOUGH GIRLS ON BIKES SOLVING MYSTERIES AND COLLECTING TREASURE. Amazing. Set on an English island in the 1980's, this game looks and sound incredible to me, and I cannot wait to play.
Knights on Bikes Trailer:
Lastly, but not leastly,
Explore, discover ruins, fight ancient monsters, all as a little adorable fox, need I say more. Well I will also say that this game is visually beautiful, it has great atmosphere, maybe the only downside is the wait, this one isn't expected until 2019 :< but that's ok, because we will have quite a few others to play in the mean time. : )
There's actually 2 more games I have to add here, they're a bit different from the 5 above, but they look too good not to mention.
The first is called 'The Last Night', let me just say, cinematic pixel sci-fi thriller in a post-cyberpunk world. Yep.
The Last Night Trailer:
The second is 'Crossing Souls', a group of friends crossing between realms, fighting and solving puzzles. With more sweet pixel graphics, and based the year I was born (1986), you really can't go wrong.
Crossing Souls Trailer:
That's my list guys, drop a comment here with any upcoming games you feel are worthy of a top 5 list.