Note that this question is touched upon here, but only for very large, expansive mods.

Also, I don't play a lot of games and have never installed a mod (and most mobile games don't allow it anyway and none on console) so this is mostly based on how much I like the concept of the mod and the footage I've seen of it, which is obviously to be taken with a grain of salt and is gonna be a lot different from a list from someone who actually plays the game with the mod. This list will also be biased towards well known mods and won't be expansive for the same reason.

KSP

Principia

Kerbal space program simplifies gravity by only doing calculations for one body generating gravity, meaning Lagrange points don't exist and orbits are generally simplified. This mod changes that, and not just for your ship, it does for the planets too.

RSS (Real Solar System) mod

Title. Basically it recreates the real solar system in Kerbal space program since KSP has it's own system with it's own planets. Usually followed by Realism Overhaul (a mod with includes real rockets because the KSP system is 10 times smaller for playability) and Realistic progression (a mod that makes all those rockets disponible in the game's tech tree and would probably be high on this list.)

Outer planets mod

Basically a mod that adds Saturn, Uranus and Neptune analogues to the game, and some of their associated satellites, while still being relatively original. (note that they do add a pluto analogue but the stock game already has a pluto analogue. It's turned into an Enceladus analogue around the Saturn analogue.)

Honorable mentions:

10x Kerbol system, because it scales up all the celestial bodies in the game to a realistic size without needing to change the rest of the game.

Tilt' em!, for adding axial tilt into the game, something that is moderately important to orbital mechanics (if your planet is inclined relative to the rest of the solar system, your orbit might need to align with the solar system instead of the planet to reduce inclination in interplanetary space.

It's Covid days and I am sure all of us who play Pen and Paper RPG's (watup, nerds) have found the experience incredibly lacking.
The way we communicate via Discord etc, has to be incredibly different from IRL conversations. Its frustrating when the core element of RPG's is the conversations, the chat, the small talk, the adlib and the silly jokes.
The way we talk IRL is so different because we can discern the different sources, we can listen more or less to different people, we can interrupt and add things. Conversations via Discord is more like listening to a speech, and then replying. IRL gaming and the conversations that crop up are more like actual human chatting - taking a joke, building on it, having it taken from you etc etc. (the way me and my friend talk is so natural, we know each other well enough to be able to discern the relevant from the irrelevant - the bits we can tag on to, and the bits we need to leave alone)

What I was thinking was to see HOW we talk in gaming, and how that could be mimicked SOMEWHAT in Discord etc.

My idea was to create a set of icons/low quality videos arranged around a table placement, that you can then focus on. Like a mouse controlled object that indicates what part of the table you focus on and how much. Just like a human would by turning her head this way or that to focus on one person talking in a group, or leaning in towards that source to indicate how much she listens to that unique source. By having a physical placement you can focus on an edge of "the table" and then lean in towards one source - and lean out to listen to all.

All other listeners can see your focus, the way you turn towards a source and be able to change their communication to fit.

So imaging having your "icon"/video at the bottom, the table sorted in a half circle shape above and your "focus" in the middle. If you pull it to its "lagrange point" (a snapping midpoint so its easy to find) you are listening to all. By dragging it towards one end you are focusing more on that person and the people around it, as a circle. You can see others focus, by coloured lines focusing more or less on an end or another.

My idea is to abuse the already available 3D audio effects existing and use that to put your focus towards one end or another, muting and muffling audio as your focus move across the table to be able to somewhat mimic the way we as human listen.

The social order of an RPG session, with the DM being the natural focus at times means that that focus can happen naturally either through focus, or simply silence. With it you can find the focus of others as an indicator of whether you are committing a faux pas or not, just like in real life when people pointedly may look directly towards another source.

I keep reading about people getting "covid insomnia". You could say, it's keeping me up at night.

Really though, it's been getting pretty regular for me. I take xanax once in a while but keeping it to an absolute minimum (no more than 0.25mg, once a week or so).

I tried the Sleep With Me podcast mentioned by @noblepath. It sort of helped. I kind of like the experience of it, the mindlessness, but I didn't continue past the second night.

It did give me the idea to just run a youtube video of rain sounds on my tv though, a lot better than what I used to do (leave netflix on some rewatches I know by heart). This is the one I'm currently enjoying: https://youtu.be/_x3hVRSIe2g