This app was mentioned in 11 comments, with an average of 1.73 upvotes
Go to device settings, there are several themes you can choose. Play store has some fore sale but read reviews because some seem to be fake. I use this one https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
I'm using this black theme but it cost a little. I'm OK with black soft keys with this theme but it's stupid that they had issues with the white one now. As for emoji if you use a different text app like textra or certain keyboards like SwiftKey you can use different systems emoji (Twitter, ios, Android, etc).
I actually called it by the wrong name. It'd Inversion for V20 / G5. $1.50 USD
https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
I have a V20, but it uses the same theme engine. You can get more themes from LG if you install their LG SmartWorld app (if your phone dose not already have it open this link on your phone to download the APK from LG) it will add a little download icon in the top right of the theme menu that you can tap and see the new themes that have been released by LG. Personally though I don't really care for any of the ones they have released so far, but there seems to be a new one or two every week or so.
Whats really cool though is its possible to install themes made by other people, and a few people from the XDA forums have figured out how to create themes and have started releasing them. Here are some links to the ones that have been released so far. I own all of them except the last 3 and they look great and work just like regular themes from LG. Inversion is really nice clean, dark theme. Vector is also one of my favorites so far. Every once in a while try searching the play store for G5/V20 themes.
https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
https://play.google.com/store/apps/details?id=com.lge.theme.charcoal.v20
https://play.google.com/store/apps/details?id=com.lge.theme.blue
https://play.google.com/store/apps/details?id=com.lge.theme.red
https://play.google.com/store/apps/details?id=com.genisys.theme.blackblue
https://play.google.com/store/apps/details?id=com.genisys.theme.blackred
https://play.google.com/store/apps/details?id=com.genisys.theme.cyan
Sure. Here is the google play page for it. https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
Here is a screenshot of the advertised text message screen: http://imgur.com/a/FilcR
And here is what I see on my phone:(note it's not black like the advertised screenshot) http://imgur.com/a/EuvDc
Try this one: https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
It is perfect if you like a monochrome dark theme.
So far I have not cared for pretty much any of the themes LG has released since the V20 launch. Thankfully its possible to install themes that are made by other people. I really like these from the play store.
https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
https://play.google.com/store/apps/details?id=com.lge.theme.charcoal.v20
https://play.google.com/store/apps/details?id=com.lge.theme.blue
https://play.google.com/store/apps/details?id=com.lge.theme.red
I belive these are all of the third party themes released so far. As long as you are running nougat they will work with the V20 or G5. I only have the V20 my self though. Keep a eye out for more, the guys that have made these themes have plans to release several more. Also I'm almost positive that if you uninstall a application from the play store within 15 minutes after downloading it you automatically get a refund. And according to this page you can manually get a refund within 2 hours of downloading.
https://play.google.com/store/apps/details?id=com.lge.theme.inverted.v20
https://play.google.com/store/apps/details?id=com.lge.theme.charcoal.v20
https://play.google.com/store/apps/details?id=com.lge.theme.blue
https://play.google.com/store/apps/details?id=com.lge.theme.red
https://play.google.com/store/apps/details?id=com.genisys.theme.blackblue
https://play.google.com/store/apps/details?id=com.genisys.theme.blackred
https://play.google.com/store/apps/details?id=com.genisys.theme.cyan