1. Twenty-Øne Pilots
2. Beautiful Eulogy
3. NF
4. Sleeping At Last
5. Florence and the Machine
A few others I love are; My Brothers and I, Jasmine Thompson, Imagine Dragons, and Ine Hoem. Ruth B, We are Messengers, KB, Jackie Hill Perry, and Aurora.

I would definitely say most, if not all of these listed produce clean music.
TØP, KB, Jackie Hill Perry, Beautiful Eulogy, We are Messengers and Sleeping At Last are all headed by Christians. Sleeping At Last is mainly instrumental, it's nice to listen before bed because they include ambient noises in their music. I could very well say the same for Beautiful Eulogy, though their music is a mixture of instruments and poetry, sung by rap artists. I highly recommend them.
I found Ruth B and Jasmine Thompson on YouTube. They have beautiful voices and I adore Ruth B's original pieces best of all. Aurora's music is similar, Indie, and I suppose you could say 'sad sounding.'
We Are Messengers are an alternative Christian band, formed in Ireland. I couldn't call them contemporary, the lyrics are excellent.
Well, I hope you get a chance to listen to at least one of these artists.

No pressure though.