There are lots of brands of luggage cubes to choose from, and I just went for the cheap Amazon Basics ones. Their key purpose is to turn a bag full of loose clothes into a bag with four or five cubes of clothes, which is a good deal easier to look through, especially at security checkpoints.
It also means that you can just move the cubes out of the bag into a hotel room's drawers when it comes time to unpack, and use them to contain dirty clothes if you're doing multiple stops. In short, they're great, and doubly so if you're doing a trip where you're staying in multiple places.
Grid-Its solve a similar type of problem, but for cables and small electronics. Their rubber-and-fabric mesh holds things sturdily, and two of the larger ones slide well into the long, thin inside pocket of the MLC. I have one packed full of chargers and recharging cables, and the other with my other electronics, like a Chromecast and router.
So let's talk about power. The most recent development here for me is that now everything I travel with takes either Micro-USB or USB-C, meaning that even if I manage to forget a specialised charger (which I have done, twice), I have four or five things that emit USB power and it's easy to buy more at most destinations.
As a quick list, this includes my phone (Pixel 3), laptop (Surface Book 2 or Surface Go), console (Nintendo Switch), portable speaker, travel router (see below) and other small items. The only missing link is my tablet - I have a slightly older iPad Pro, because having a tablet with LTE built-in is important to me - but if and when I upgrade to the shiny new iPad, that will be fixed too.
The key thing I've found with power is having duplicates of everything I have at home and keeping the set of duplicates as a permanent travel set. This is easily done for USB-C and USB Micro cables, but a little more expensive for Surface chargers and Garmin watch cables. Still worth it, though.
I also have a couple of goes-into-anything power adapters. There's so many of these a brand recommendation isn't worth it, but make sure it has at least 4 different types of socket it can plug into and it has some USB ports on the bottom to charge with. It means you basically never need to worry about digging out country-specific adapters again.
Finally, while I travel with a couple of USB batteries, my favourite is the Omnicharge Omni 20. It has an integrated AC power socket, which is handy for powering anything electronic if you have no other choice, as well as direct DC power output for laptops, and the ability to safely charge off of any DC input - 5 volts up to 24 volts. You can hook that thing up to a solar panel and it'll regulate itself if you need it, all while being well inside the limits of lithium-ion batteries that are allowed on airplanes.
Data & Internet
Having fast data everywhere for no extra cost is the dream, and for many years I thought I'd never see it - my old Kindle Keyboard was the only device that had free global internet, and I took it everywhere as a backup, even using it on my first trip to Kiev to slowly load a phrasebook to try and order food.
These days, though, I am a happy user of Project Fi, which, for US residents, offers internet in pretty much any country you might travel to for no extra cost. T-Mobile US do this as well, but they limit you to 2G speeds, whereas Fi gives you 3G or LTE depending on the country. If you live elsewhere, offerings are less good, but they're improving. Someday, I'm hoping that Iridium Next or another satellite solution will get cost-competitive enough to make it possible to get internet access anywhere on Earth.
Until then, I also take an InReach communicator with me whenever I go somewhere that's relatively off-grid (where I'm unsure I'm going to have a mobile signal). They don't offer much in the way of data services, but they offer weather for your current location, text messaging, a live GPS-tracking map for others to see, and an SOS button, all of which are quite reassuring when you're a day's kayak up an Australian river or camping in the middle of Death Valley.