Pawns can (and will) die. Raiders have families (as can be seen in their relationship tab) and will die. Pawns will be near-inconsolable for (the real-world equivalent of) months if a close family member dies. (e.g. a spouse, a child, or a sibling)
The new dlc, Biotech, adds arenthood, and one of the mentalbreaks causes a pawn to leave the colony, that pawn can be a parent to one of your child pawns
You can have gladiator fights involving females. However, this is optional.
If you want to finish someone off, the only way is to beat or shoot them to death. This can involve a female colonist. (Of course, this isn't really for spectacle, unless the pawn doing the beating has the "bloodlust" trait, giving them pleasure after killing someone.
There is slavery added with Ideology, and one of the mentalbreaks that can happen is called Sadistic Rage, that will cause the afflicted pawn to abuse your prisoners, that pawn can be a slave
Children can be shot, beaten, and killed by anyone, including your own colonists. Children can appear in raids, though this is typically off by default. Since children are so weak, it's VERY easy to kill them.
There are many drugs, including weed and (crack) cocaine. You can assign colonists to not do any drugs (though some do love them and will complain when they don't have them.)
There are various drugs in the game, each analogues to real-life drugs: beer, psychite tea (an analogue to coca leaf tea), smokeleaf joints (an analogue to weed), wake-up (an analogue to methamphetamine), go-juice (which seems to be a cocktail of addictive anabolic steroids?), as well as flake, yayo (analogues to crack cocaine and cut cocaine, respectively.), and luciferium (a fantasy drug with no realistic counterpart).
Your colonists can, if you so choose (or if a colonist with the Chemical Fascination trait undergoes a Drug Binge mental break, automatically), use these drugs. They can develop addiction, and if you run out or want them to stop, suffer withdrawal effects ranging from mood debuffs to (exclusive to luciferium) instant death.
You can butcher animals, including pets, and starve them deliberately. With certain mods, you could even lobotomize them, though the player can choose to not install those mods.
Dogs can fight eachother in several circumstances (two wild dogs battling for food, a tamed dog fighting a wild dog, and a tamed dog battling one that's infected with scaria).
There are genetically modified bugs that don't resemble real ones, though their description in the information menu does entail what bug they were mutated from.
In social fights (fights between pawns that are a result of them disliking each other) pawns will assault each other, regardless of gender, though slapping does not occur. Also, fights are not animated, and if you want to know everything that happened in the fight you can go into the colonist's log.
Colonists below the age of 16 cannot get into romantic relationships, and for the next year or so it remains difficult for them to get into relationships. Relationships are also less likely when there's larger age gaps.
the "Ideoligy" DLC adds a styling table that can be used to change a colonists hair, beard or tattoos. however nothing is shown as the colonist basicly just pops a new haircut on when useing the table
you can use the 'euthanize by cut' operation, which slices the throat of a pawn. in addition, attacks can hit pawn's necks, though it isn't very graphic
decapitation can happen from a variety of causes. Additionally, players can order one of their colonists to extract the skull from a corpse, effectively decapitation them
If you mine too far under a mountain and don't put up supports for the roof, there's a chance your colonist will get crushed when it collapses. It is a very quick process, and they kind of just poof off the screen though. It's not graphic at all.
When raiding a faction's base, if you choose to, there will sometimes be a baby which you can adopt, raiders who attack your colony can also kidnap babies and children too
Biotech adds children, and when a setting is enabled, they can and will become raiders who can attack your colony, you will need to kill them as there is no reasoning with any raiders in the game
Biotech adds children's toys that can be built, a pawn can have a mental break called Tantrum, and can choose to break a specific thing, or just attack different structures, one of the things that can potentially be destroyed is the child toys you build
There is cannibalism in the game, but the human who is eaten is not alive, and animals can also eat corpses, but will attack a human until they die and then eat them
There aren't mechanics in game for trans people, but there are pawns with pregenerated backstories, and the only one of these that is trans is just a regular jeweler.
There are player-submitted pawns that have custom backstories, and the backstory for Alyssa 'Sparkles' Orchard reveals that she's transgender and contains her birth name. She cannot otherwise be deadnamed unless you deliberately change her nickname to it, and there are no mechanics that allow for other characters to have deadnames at all.
Pawns can go insane for periods of time via catharses, where they will beat, murder, dig up corpses and wander around (even mid-combat). This is pretty much all of the above.
Body purists, who hate the idea of artificial body parts, can be given them anyway. They very much despise this.
Conversely, body modders and transhumanists have some dysmorphia if they have no artificial body parts.
Technically it's possible - character can self-harm and bleed out, but self-harm is rare issue and in most cases it's possible to help self-harming character. Characters can also perish in explosions caused by themselves.
the babys added by the "Biotech" DLC can cry however they don't make any sound and due to the games simple graphics they don't even look like they are crying. the only effect this has is lowering the mood of any colonist who hear them
Pawns below 16 can't get into relationships, and it's hard for another couple years, especially with large age gaps, but it remains possible. I have a save where a 16 year old got into a relationship with a 43 year old.
the games "Ideogy" DLC lets ideogy's be based on either a generic religion, no religion or a real religion (Buddhist, Christian, Hindu, Islamic). however these religions are purely cosmetic and have little to no inpact on gameplay
With the Biotech DLC, using the xenotype creator you can create pawns that resemble demons though they are not actual ones.
Within the lore, tribes refer to mechanoids (hive-minded war machines) as demons from a vengeful god.
You can have naked colonists, and some prefer to be naked, but the lack of detail in pawns means that you only see skin-colored blobs. (And all skin-colored blobs are not necessarily naked, as pants do not show up on pawn models.)
Sex is exclusively referred to as lovin' and it is not depicted at all besides putting some floating hearts around the shared bed where lovin' is happening.
Characters can be masochists, and instead of getting a mood penalty from pain they get the opposite response (e.g. -5 mood from minor pain is turned to a +5, with the maximum being mind-shattering pain, giving +20).
Any pawn can have a mindscrew installed into their brain, regardless of whether or not they are a masochist. If the implant is installed, non-masochists will receive -10 and vice versa.
There is an event in the game called Wild Person, where they are essentially treated like an animal by the game, and they live outside your base in the dirt