Spotify isn't doing anything unique here, and it's not really a marketing campaign to explain away their UI. It's more of a showcase for hiring professionals, developers/designers/etc. Facebook has a similar one -> https://design.facebook.com/. Source: almost 3 years ago

Also, read anything published by Design @ Facebook. Source: over 3 years ago

I would throw in a bright background, filling the screen. Yellow, green, something that makes it really pop. Make it modern and sleak, no box shadows or glimmer, go bold with typography and throw in some illustrations. Icons8 have some truly unique free vector illustrations, https://icons8.com/illustrations, I use them all the time in my designs. Source: over 1 year ago

No, I wish I was that talented. I found them on Ouch you can download a free png version as long as you mention the artist and the website on your project, it's in my footer! Source: over 2 years ago

They're called vector illustrations just for reference, and as a few other folks have pointed out, there's a ton of resources out there (free and paid) for finding vector illustrations of all different styles you can use (Icons8, unDraw, etc.). Source: over 2 years ago

I like the diversity on Icons8: https://icons8.com/illustrations - and they're free to use with attribution. Source: over 2 years ago

Icon8 not only provides us with a huge collection of vector icons, but vector-based illustrations as well (Ouch!). Illustrations are grouped into categories and we can search for any type of vector illustration using the search bar. - Source: dev.to / almost 3 years ago