Update 3:Added 8 new themes
Update 2:Added Liv Dark, PitchBlack
Update 1:Added Valerie, Flux

Substratum provides the ability to theme your system and third party apps. Substratum has been here since android nougat and its still being managed. It was possible for people to use substratum even without root , but only upto Android 8.1. With Android Pie google has restricted the use of overlays on non-rooted devices. There is no to install them without root.

So now if you are on Android 10 and want to use substratum themes then you need a rooted device. At this moment of writing this,  Android Q is still in beta stage and has been available to the app developers and for different devices for testing their apps and giving feedbacks.

There are new themes started popping up for Android 10 on play store. I will list all the Android Q supported substratum themes here in this post once they come out and will try to keep the post updated.

For using substratum themes on Android Q , you need to be rooted with Magisk and need to install the  Substraum Lite  app. This is the lite version of the popular Substratum theme engine. The main substratum theme engine app does not support Android Q as of now but we can expect to get it working in near future. Substratum lite supports Android Q and still being developed and improved for better compatibility with android.

How to apply themes with substratum lite -
Make sure you have Magisk and a Android Q compatible theme installed.

  1.  Install the substratum lite theme engine from play store.
  2.  This app will automatically install its magisk module.
  3.  Reboot
  4.  Open substratum lite again and click the theme you installed.
  5.  Install all overlays and reboot
  6.  Open substratum lite and click on Manage , select all overlays and enable them.
  7.  Enjoy 

List of themes -

1.

Ethereal -

This theme is in beta testing (update: out of beta and stable now) but it works really well android Q. I have used it on Q personally, its a simple theme with most of the popular apps theme support. The best things about this is the the custom icons, simple and minimal. Unlike other themes size of this theme is very just about 3-4 MB. You need to join the beta testing in order to use this theme on Q. Its a paid theme.
NameEthereal
DownloadPlay Store

2.

Outline -

This theme is also in beta testing (update: out of beta and stable now) but it works really well android Q. This is the white version of the Ethereal theme. You need to join the beta testing in order to use this theme on Q. Its a paid theme.
NameOutline
DownloadPlay Store

3.

Outline X -

This is not a theme, it is just an extension of the Outline and Ethereal themes. It provides more color options to choose from and some other tweaks for the theme. You can even generate Telegram and Telegram X themes from it.
NameOutline
DownloadPlay Store

4.

Substweaks -

This is also not a theme but it provides a variety of tweaks for for the user interface. It might not be fully supported on Q because its not updated from some time but you can give a try. I have personally tested this but not all the options from it. I just used it to change the number of columns in notification bar and it worked well for me.
NameSubstweaks
DownloadPlay Store

5.

Valerie -

Valerie is a well known substratum theme due to the wast numbers of custom icons, colors and customizations options. It supports AOSP Android 10 for theming just like the rest of the themes I mentioned above. It also supports OxygenOS based on Android 10. This is also a paid theme.
NameValerie
DownloadPlay Store

6.

Flux White/Black-

Flux theme for Substratum theme engine is designed with pixel perfect graphics and material ui, to give your phone a new vibrant and dark look. It supports AOSP Android 10 for theming just like the rest of the themes I mentioned above.It does not support OxygenOS as of now. This is also a paid theme.
NameValerie
Download Black Version Play Store
Download White Version Play Store

7.

Liv Dark-

Another wonderful theme with gradients and a lot custom icons and customization options. It supports • Android Pie/10 stock and custom roms, Oxygenos Pie/10 and Samsung Pie. Its a paid theme.
NameLiv Dark
DownloadPlay Store

8.

Pitch Black-

A well known theme in Android theming community since a long time. It supports Android 10 (Pixel and AOSP),Android Pie (Pixel and AOSP), Android Pie OxygenOS, Android Oreo aosp 8.0/8.1 & Pixel/2, Android Oreo OxygenOS 8.0/1, Android Nougat aosp 7.1 OMS. Its a paid theme.
NamePitchBlack
DownloadPlay Store

9.

Liv White-

Its the white version of the popular liv dark theme.
NameLiv White
DownloadPlay Store

10.

Swift Installer -

Its not a substratum theme, its a standalone theming engine which does not require substratum app. It provides the ability to choose your own background and accent colors using color picker, you can also use hex color values. All you need is to select colors and build overlays and reboot.
NameSwift Installer
DownloadPlay Store

11.

Biohazard

NameBiohazard
DownloadPlay Store

12.

Translucent

The name says everything about this theme. :p
NameTranslucent
DownloadPlay Store

13.

Flare

Another theme from the developer of Valerie theme. This one has gradient things in it.
NameFlare
DownloadPlay Store


14.

FAB

A simple and minimalist eye catching theme with some sleek custom icons. Its the dark version.
NameFAB
DownloadPlay Store

15.

Belo

A simple and minimalist eye catching theme with some sleek custom icons. This is the white version of FAB theme.
NameBelo
DownloadPlay Store

15.

Gravija

Another nice and minimal theme with colourful icnons all over the places :p
NameGravija
DownloadPlay Store

So only these themes/tweaks works for now on Android Q. If you know any about theme which got support for Android Q , please tell in the comments section. If you have any questions you can ask here in comment box or in our telegram group @thespandroid.