Gramatik comes to mind, so does GRiZ and The Floozies, but those acts lean more on the funky side, whereas I've always associated Oliver with more a disco and 80s feel, similar though. Another one would be Madeon, I love Oliver's remix of Madeon's "You're On" (https://soundcloud.com/madeon/youre-on-ft-kyan-oliver-remix). Also some of Mat Zo's more funky/disco-y music, AND Lemaitre too!
I looooovvvvvveeeeee Oliver though, definitely one my favorite groups out there, wish more people were aware of them (or at least where I'm from hah). It took me a little bit to think of something similar, because Oliver has such a distinct sound, that aspect of their music is something any producer should aspire to, imo!
Here are some links from the aforementioned artists:
https://soundcloud.com/griz/summer-97-ft-muzzy-bearr?in=griz/sets/chasing-the-golden-hour-pt-1
https://soundcloud.com/griz/get-down-ft-sunsquabi-and-manic-focus?in=griz/sets/say-it-loud
https://soundcloud.com/griz/simple-ft-the-floozies?in=griz/sets/rebel-era-1
https://www.youtube.com/watch?v=BC_Ya4cY8RQ
https://www.youtube.com/watch?v=tAhT6kFWkAo
https://www.youtube.com/watch?v=PgDMeLEqvYY
https://www.youtube.com/watch?v=iqkzR0sdtuU
https://soundcloud.com/matzo/soul-food-club-mix
https://soundcloud.com/matzo/mat-zo-ft-the-knocks-get-down-2-get-up
I literally know every artist and every song you posted xD hahaha all good stuff.
I mean specifically that 80s house vibe. I tweeted at them once saying their sound is like an 80's version of the future and they told me that that's EXACTLY what they were going for. It's just so unique I literally think that there isn't a single other artist who makes music like them, or even closely similar. I just want more Oliver ALLL the time. I found out who they were like 2 weeks after they JUST came to town. Haven't been back since. Still so so so so so sad about that one. I need them in my life all the time.