I don't think all these are contemporary but as someone who loves post rock and instrumental music here are some artists that make it into my playlist pretty regularly. Hope this is helpful! The ones near the top I probably listen to more regularly right now but it tends to rotate.
- Sleepmakeswaves
- We Lost the Sea
- Explosions in the Sky
- Codes in the Clouds
- Ef
- Russian Circles
- Collapse Under the Empire
- Mogwai
- Secret Gardens
- Red Sparowes
- Moonlit Sailor
- Maybeshewill
- 65daysofstatic
- Caspian
- Sleep Dealer
- If These Trees Could Talk
- Balmorhea
- God is an Astronaut
- The Evpatoria Report
- Sigur Ros
- False Horizon
- This Will Destroy You
- pg.lost
- There's A Light
- Oh Hiroshima
- Tides from Nebula
EDIT: got around to checking my library and have a few more.
- Distant Dream
- Saor
- Those Who Ride With Giants
- For Giants
- U1327
- The Best Pessimist
- Saxon Shore
- Dorena
- The End of the Ocean
- Random Forest
- Joy Wants Eternity
- Paint the Sky Red
- Eldamar
- we.own.the.sky
- Eleventh Vibration
- Shadow of Io
- Jake Eves
- The Last Sighs of the Wind
In hindsight I don't know if a giant list is the most useful thing but it's here if you want it.