The mysterious obelisk will begin getting attacked by enemies once you approach. You will need to defend it from multiple waves of enemies. Luckily, the obelisk has a decent health bar, but be aware you can damage it yourself.

Bonsaire, The Illuminated can typically be found wallowing in his sorrows facing a wall. Upon attacking him, he will become very hostile using ranged and melee attacks that deal quite a lot of damage. He also becomes quite cowardly after a long engagement and will flee the area. You typically cannot catch up to him, so it might be best to meet up with him later.

This is the soul trap. Once you activate it you will need to kill the enemies and allow their souls to enter the trap. If you stand in the way of the souls they will damage you. Each soul you collect will give you one demonic weapon ammo. This is a great thing to leave for last and then stock up on demonic ammo before the boss fight!

First, you will come upon an open book.
Upon interacting with the book, you will have a blue witchfire trail at the bottom of your screen (see below). You will want to follow the direction of the witchfire trail to your treasure (think of it like a compass).
It is also worth noting that there is a time limit, although it is rather generous if you don't encounter any enemies on your way to the treasure.

While restless spirits do not appear as dangerous areas or events, I figured they were worth mentioning. They are easily spotted from a distance by their glowing red orb. They also make a loud ringing noise that is rather distinct.
Upon approaching the orb, you will note "You come upon a restless spirit. It seems to try to lead you somewhere." There will now be red footsteps you can follow to reach a cursed treasure.

The restless soul begins as a tombstone which you can approach.
Upon reaching out to the restless spirit, a wisp will spawn. You will want to follow it, but be aware it will spawn enemies along it's path.
Eventually, the wisp's energy will be expended and you will receive your rewards.

Rituals are one of the more difficult events to complete; there is a boss fight that you will need to be decently prepared for.

Note: On Scarlet Coast, sometimes the ritual will continue to spawn totems that prevent you from damaging the boss, even after you have finished the ritual. This can make killing the Galley Slave a lot more challenging, so beware.

The Magic Focus Orb requires you to be in focus. You can obtain focus by defeating enemies without being hit. (if someone has a better explanation of the focus system, please enlighten me as I have no clue how it works.)
Upon obtaining focus, you will see a yellow sphere floating above the altar.
You will need to find 3 hexes, which you can only see by looking through the orb. These can be tricky, but try your best to use the clicking sound they make to locate them.

The Explosive Package event can begin at a chopping block - which is marked on your map.
Upon interacting with the corpse, an exclamation point will appear on your minimap.

You will want to travel to the point and pick up the severed head.
The key to successfully transporting the head is to move slowly. My best recommendation is to walk until it sets fire, and then crouch walk until the fire goes away. Repeat until you arrive at the severed head's corpse. Thanks to the comments, it seems the best way to transport the head is by running and then immediately sliding, and repeating this until you run out of stamina. While out of stamina I recommend staying crouched.
There is currently, what I believe to be, a glitch that allows you to pick up the head and continue running without it setting fire. To do this, you must start running and continue holding sprint while picking up the head. Once you pick up the head, you must keep sprinting otherwise the head will begin to ignite again, as normal. Be aware that if you step over something as small as a piece of debris that makes you "fall", it will reset the head and allow it to ignite. I believe this is a glitch so it may get patched in the future.

Rarog's Egg is typically found in between three pillars.
Upon igniting it, enemies will begin to spawn (from what I've noticed, only woodsman and their speedier relatives spawn). The egg will also begin to pulsate a fiery aura; the pulsation will damage you, so I recommend putting an obstacle in between you and the egg. Upon successfully defending the egg, you will be able to break the shell.
Once you break the shell, a burnt corpse will appear. You need to shoot it to receive the rewards.

Fallen conquerors can be easily distinguished on the map because of the loot bag symbol (see below).
They will typically ask you for either a signaculum or a goblet.

Gatekeepers are irritating obstacles preventing you from traversing the area. They typically start opaque, but you can shoot or slowly approach to reveal them.
To destroy the gatekeeper, you will need to find 2 hexes (shown below), with one on each side of the gatekeeper totem. It is easiest to use their clicking sound to find the location.
You will need to match the aura's color to that of the gatekeeper totem to destroy the hex without being damaged. For simplicity, blue when blue, orange when orange.

Gatekeeper chests function similar to gatekeepers. There will be six hexes around the chest. You will need to match the color of the center totem to the hex you are shooting. The color will change each time and you need to quickly shoot all 6. This one can be a little tricky.

The cursed crystal can be found surrounded by vile pustules which explode upon your proximity. To receive your reward, simply shoot the crystal and the surrounding traps will disappear.

If you see an event on your map and hold your mouse over it, you will typically see the potential rewards for completing it. For mushrooms, this is not the case. This makes it easy to determine using only the map. The event is simply a mushroom patch. Make sure to eat the correct mushrooms to avoid poisoning.

A quick reference for the mushrooms can be found here. Special thanks to u/ZOG_WAS_HERE for the picture.