I really enjoy How Long to Beat. It's nice getting to know beforehand if I'm about to open a 10h casual game or a 120h massive undertaking, specially given the portable nature of the Deck.
Shameless plug but I just re-released my Volume Mixer plugin to the store. It allows you to control the volume of games, programs, and connected Bluetooth sources like phones. I use it all the time since I usually have a podcast or stream going on my phone while playing a game
Yup! The Steam Deck (or Linux really) lets you use it as a Bluetooth speaker. So I connect my phone to the Deck and my AirPods to the deck and can listen to anything that’s playing through my phone and the deck through my headphones.
My personal favorite is Pause Games. Not only does it fix sound issues with sleep in most games, but it allows me to run multiple games at once and swap between them without it hurting performance/battery.
Autoflatpaks is great, but I don't think it updates all of my flatpaks. Seems like whenever I do switch to desktop I always have a bunch that are not updated even though autoflatpaks has been downloading updates regularly.