I use a few patches on mine, most notably removing the links on the bottom of the home screen and unifying font sizes between epubs and kepubs. Patches can run the risk of bricking your device, but as long as you follow the instructions you should be fine. There’s a relatively new
GUI made to help install them, too. I haven’t run into any issues yet. They are reversible if you decide you don’t like the changes.
I also use
NickelClock. If it’s something you’re interested in, I’d highly recommend it.
I wouldn’t consider KOReader essential for a Libra 2. Especially with patches, the stock reading experience is very nice. I use KOReader mostly on my Libra 2 because it’s exclusively what I use on my mini.
NickelMenu is great on the Libra 2: adding its icon to the bottom of the home/library screens makes it feel like there’s less extra negative space. I also appreciate being able to navigate to Pocket or the web browser with only two taps.