Pasted

30 March 19: Updated the IP addresses
 You can block Spotify ads if you just null(?) them, just add this in your hosts File.
On windows is at C:\Windows\System32\drivers\etc\hosts file. 
On Mac open finder and type /private/etc/hosts
On Linux edit /etc/hosts
More info here -> https://en.wikipedia.org/wiki/Hosts_(file)
 0.0.0.0 media-match.com
0.0.0.0 adclick.g.doublecklick.net
0.0.0.0 pagead2.googlesyndication.com
0.0.0.0 desktop.spotify.com
0.0.0.0 googleads.g.doubleclick.net
0.0.0.0 pubads.g.doubleclick.net
0.0.0.0 audio2.spotify.com
0.0.0.0 vortex.data.microsoft.com
0.0.0.0 vortex-win.data.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com.nsatc.net
0.0.0.0 oca.telemetry.microsoft.com
0.0.0.0 oca.telemetry.microsoft.com.nsatc.net
0.0.0.0 sqm.telemetry.microsoft.com
0.0.0.0 sqm.telemetry.microsoft.com.nsatc.net
0.0.0.0 watson.telemetry.microsoft.com
0.0.0.0 watson.telemetry.microsoft.com.nsatc.net
0.0.0.0 redir.metaservices.microsoft.com
0.0.0.0 choice.microsoft.com
0.0.0.0 choice.microsoft.com.nsatc.net
0.0.0.0 df.telemetry.microsoft.com
0.0.0.0 reports.wes.df.telemetry.microsoft.com
0.0.0.0 wes.df.telemetry.microsoft.com
0.0.0.0 services.wes.df.telemetry.microsoft.com
0.0.0.0 sqm.df.telemetry.microsoft.com
0.0.0.0 telemetry.microsoft.com
0.0.0.0 watson.ppe.telemetry.microsoft.com
0.0.0.0 telemetry.appex.bing.net
0.0.0.0 telemetry.urs.microsoft.com
0.0.0.0 telemetry.appex.bing.net:443
0.0.0.0 settings-sandbox.data.microsoft.com
0.0.0.0 vortex-sandbox.data.microsoft.com
0.0.0.0 survey.watson.microsoft.com
0.0.0.0 watson.live.com
0.0.0.0 watson.microsoft.com
0.0.0.0 statsfe2.ws.microsoft.com
0.0.0.0 corpext.msitadfs.glbdns2.microsoft.com
0.0.0.0 compatexchange.cloudapp.net
0.0.0.0 cs1.wpc.v0cdn.net
0.0.0.0 a-0001.a-msedge.net
0.0.0.0 statsfe2.update.microsoft.com.akadns.net
0.0.0.0 sls.update.microsoft.com.akadns.net
0.0.0.0 fe2.update.microsoft.com.akadns.net
0.0.0.0 65.55.108.23
0.0.0.0 65.39.117.230
0.0.0.0 23.218.212.69
0.0.0.0 134.170.30.202
0.0.0.0 137.116.81.24
0.0.0.0 diagnostics.support.microsoft.com
0.0.0.0 corp.sts.microsoft.com
0.0.0.0 statsfe1.ws.microsoft.com
0.0.0.0 pre.footprintpredict.com
0.0.0.0 204.79.197.200
0.0.0.0 23.218.212.69
0.0.0.0 i1.services.social.microsoft.com
0.0.0.0 i1.services.social.microsoft.com.nsatc.net
0.0.0.0 feedback.windows.com
0.0.0.0 feedback.microsoft-hohm.com
0.0.0.0 feedback.search.microsoft.com
0.0.0.0 media-match.com
0.0.0.0 adclick.g.doublecklick.net
0.0.0.0 www.googleadservices.com
0.0.0.0 localhost
0.0.0.0 pagead2.googlesyndication.com
0.0.0.0 desktop.spotify.com
0.0.0.0 googleads.g.doubleclick.net
0.0.0.0 pubads.g.doubleclick.net
0.0.0.0 audio2.spotify.com
0.0.0.0 www.omaze.com
0.0.0.0 omaze.com
0.0.0.0 bounceexchange.com
0.0.0.0 pubads.g.doubleclick.net
0.0.0.0 securepubads.g.doubleclick.net
0.0.0.0 www.googletagservices.com
0.0.0.0 gads.pubmatic.com
0.0.0.0 ads.pubmatic.com
0.0.0.0 spclient.wg.spotify.com
0.0.0.0 image2.pubmatic.com
0.0.0.0 ads.pubmatic.com
0.0.0.0 sync.rhythmxchange.com
0.0.0.0 tpc.googlesyndication.com
0.0.0.0 m.goadservices.com
0.0.0.0 pagead2.googlesyndication.com
0.0.0.0 ut.performax.cz
 If you are using mac, replace 0.0.0.0 with 127.0.0.1, so basically:
127.0.0.1 media-match.com
127.0.0.1 adclick.g.doublecklick.net
127.0.0.1 pagead2.googlesyndication.com
127.0.0.1 desktop.spotify.com
127.0.0.1 googleads.g.doubleclick.net
127.0.0.1 pubads.g.doubleclick.net
127.0.0.1 audio2.spotify.com
127.0.0.1 vortex.data.microsoft.com
127.0.0.1 vortex-win.data.microsoft.com
127.0.0.1 telecommand.telemetry.microsoft.com
127.0.0.1 telecommand.telemetry.microsoft.com.nsatc.net
127.0.0.1 oca.telemetry.microsoft.com
127.0.0.1 oca.telemetry.microsoft.com.nsatc.net
127.0.0.1 sqm.telemetry.microsoft.com
127.0.0.1 sqm.telemetry.microsoft.com.nsatc.net
127.0.0.1 watson.telemetry.microsoft.com
127.0.0.1 watson.telemetry.microsoft.com.nsatc.net
127.0.0.1 redir.metaservices.microsoft.com
127.0.0.1 choice.microsoft.com
127.0.0.1 choice.microsoft.com.nsatc.net
127.0.0.1 df.telemetry.microsoft.com
127.0.0.1 reports.wes.df.telemetry.microsoft.com
127.0.0.1 wes.df.telemetry.microsoft.com
127.0.0.1 services.wes.df.telemetry.microsoft.com
127.0.0.1 sqm.df.telemetry.microsoft.com
127.0.0.1 telemetry.microsoft.com
127.0.0.1 watson.ppe.telemetry.microsoft.com
127.0.0.1 telemetry.appex.bing.net
127.0.0.1 telemetry.urs.microsoft.com
127.0.0.1 telemetry.appex.bing.net:443
127.0.0.1 settings-sandbox.data.microsoft.com
127.0.0.1 vortex-sandbox.data.microsoft.com
127.0.0.1 survey.watson.microsoft.com
127.0.0.1 watson.live.com
127.0.0.1 watson.microsoft.com
127.0.0.1 statsfe2.ws.microsoft.com
127.0.0.1 corpext.msitadfs.glbdns2.microsoft.com
127.0.0.1 compatexchange.cloudapp.net
127.0.0.1 cs1.wpc.v0cdn.net
127.0.0.1 a-0001.a-msedge.net
127.0.0.1 statsfe2.update.microsoft.com.akadns.net
127.0.0.1 sls.update.microsoft.com.akadns.net
127.0.0.1 fe2.update.microsoft.com.akadns.net
127.0.0.1 65.55.108.23
127.0.0.1 65.39.117.230
127.0.0.1 23.218.212.69
127.0.0.1 134.170.30.202
127.0.0.1 137.116.81.24
127.0.0.1 diagnostics.support.microsoft.com
127.0.0.1 corp.sts.microsoft.com
127.0.0.1 statsfe1.ws.microsoft.com
127.0.0.1 pre.footprintpredict.com
127.0.0.1 204.79.197.200
127.0.0.1 23.218.212.69
127.0.0.1 i1.services.social.microsoft.com
127.0.0.1 i1.services.social.microsoft.com.nsatc.net
127.0.0.1 feedback.windows.com
127.0.0.1 feedback.microsoft-hohm.com
127.0.0.1 feedback.search.microsoft.com
127.0.0.1 media-match.com
127.0.0.1 adclick.g.doublecklick.net
127.0.0.1 www.googleadservices.com
127.0.0.1 localhost
127.0.0.1 pagead2.googlesyndication.com
127.0.0.1 desktop.spotify.com
127.0.0.1 googleads.g.doubleclick.net
127.0.0.1 pubads.g.doubleclick.net
127.0.0.1 audio2.spotify.com
127.0.0.1 www.omaze.com
127.0.0.1 omaze.com
127.0.0.1 bounceexchange.com
127.0.0.1 pubads.g.doubleclick.net
127.0.0.1 securepubads.g.doubleclick.net
127.0.0.1 www.googletagservices.com
127.0.0.1 gads.pubmatic.com
127.0.0.1 ads.pubmatic.com
127.0.0.1 spclient.wg.spotify.com
127.0.0.1 image2.pubmatic.com
127.0.0.1 ads.pubmatic.com
127.0.0.1 sync.rhythmxchange.com
127.0.0.1 tpc.googlesyndication.com
127.0.0.1 m.goadservices.com
127.0.0.1 pagead2.googlesyndication.com
127.0.0.1 ut.performax.cz
Additional Step for Mac: Close spotify, right click it, select 'Open Package Contents', then navigate to 'Contents/Resources/Apps' and delete 'ad.spa'
 Add the following ip ranges to your router or firewall (optional)
 31.13.76.102
173.194.0.0-173.194.255.255
216.58.192.0-216.58.223.255
74.125.0.0-74.125.255.255
2.16.4.0-2.16.4.255
74.125.136.0-74.125.136.255
173.194.65.0-173.194.65.255
23.235.43.0-23.235.43.255
194.68.165.0-194.68.165.255