None.

If it doesn't work completely with the remote I don't even bother.

None. Got fed up of connecting a mouse to the TV. If I cannot control it with a remote, its not gonna be sideloaded.

Mainly just web browsers. Use my Shield controller as the mouse.

Tasker

together with Button Mapper makes my Sony bravia remote much more powerful.

Adguard

Firefox browser, PIA vpn for netflix

Wireless keyboard mouse combo always connected to the Tv.

Google maps

Chrome

Bacon reader (for Reddit)

Edit: I have a $20 remote with mouse and keyboard

Hulu...because no live tv on native android tv app

SD Maid Pro. It is possible to install it from the Play website. The interface is fully usable with a remote. Not sure how necessary it is though.

DNS66 as ad blocker and DNS changer even for non rooting devices, also avoids apps that check for Adblockers to avoid the detection. ProgTV - this is the best ever apk for IPTV, also plays other streams and records everything that it plays. Xplorer as filemanager, supports about every protocols without any other plugins. Noxbit, well you have to figure what it does, when you do it you'll love it.

As other has pointed out: None. All the Apps I need on my Android TV device are there.

Does MX Player count?

Only Chrome. Mainly for download links. I copy the URL on my phone, open Android remote tv app, click the Mic button and paste the link.

pushbullet so i can send myself links and files. need a mouse or touchpad though. i use 2 in 1 keyboard/touchpad

Just Firefox cause i don't like to turn on my computer if I need to check something.

YouTube. tv version sucks. why is everyone against a TV having a mouse and keyboard?

Sky Go

MXQ 4K Box - with

ES File explorer

Sd Maid

Aptoide TV

Livenet.t Redbox TV

Terrarium TV

Puffin tv

Acestream Player

Youtube

AC Market

don't use any of em that much at all if I'm honest

Mcafee and Malwarebytes