[quote=“Coolthulhu, post:2, topic:9584”]Mind powers like telekinesis and telepathy are generally out, but some more mundane mind powers could be OK.
Things like berserk, morale alterations, calculation of projectile path etc. - those would probably be fine.[/quote]
IMO telekinesis would be the only “magical” mutation i would accept but not necessary for combat situations, maybe to get a far away item that is between a danger zone (lava, traps) like that CBM which name i can’t remember that lets you pull metallic items, and yeah those powers you mentioned may be possible, these are my my ideas:
[glow=yellow,2,300]Neutral[/glow]
Irregular Head - Your head has grown slightly, this doesn’t give any effect, you can still wear headgear though.
This is the first stage for later mutations.
Strange Thoughts - You sometimes think unusual things unexpectedly, this doesn’t affect you in any way.
[glow=green,2,300]Positive.[/glow]
Fast Learner
Good Memory
Psychopath
Self-Aware
Optimist
Fast Reader
Suppress Pain (Active) - You steadily focus to lessen the pain you are suffering. You need to be undisturbed to this mutation to take effect.
Basically this allow to reduce gradually a quantity of pain but only if you are out of combat and has fairly long cooldown.
Lucid Dreams (Passive) - You will usually have total control of your dreams when sleeping, resulting in high morale bonuses.
Everytime you sleep, there a chance you will wake up with a morale boost, this could be 70-100 (This can change) slowly decreasing.
Calculation (Passive) - Quickly studying your prey’s movement patterns and reactions times, you can determine the trajectory of ranged weapons and a chance to make pinpoint shoots, resulting in better accuracy and critical chances.
Maybe this looks overpowered, it could be split in two separates mutations
Neuro-Regeneration (Passive) Your head regenerates better than the rest of your body when you sleep, resulting in more HP gain. Stacks with Fast Healer.
Self-Explanatory
Dim Suggestion (Passive) You subtly charm a NPC when you talk to them, resulting in better affinity; bargains, lying, etc.
Yeah, i don’t have a good description for this one :P, simply you get more chance to get equipment, better deals, intimidate with NPCs.
Frenzy (Active) You enter into a state of rage, increasing melee damage and speed as well, when the effect ends you will get a penalty.
A good one for melee users, the debuff would be something like reducing certains stats, pain or maybe losing some HP.
[glow=red,2,300]Negative[/glow]
Slow Reader
Slow Learner
Glass Jaw
Insomniac
Schizophrenia (This one could be removed of the branch)
Migraine (Passive) - You rarely experiment unpleasant headaches, resulting in reduced Intelligence, a bit of pain and small accuracy penalty.
The frequency could change, a tough enemy for book lovers.
Dreadful Thoughts (Passive) - You may experience nasty visions or hear abhorrent phrases in your mind, resulting in morale penalties.
This can occur randomly, the severity of the morale penalty may vary, from 20 to 85, of course this value can change, as a added bonus the messages can appear on the message box, like mi-go’s saying their curious catchphrases.
Dizziness (Passive) - Randomly you suffer a light disequilibrium, making you slightly move to any direction.
Watch out lurking in missiles silos with this trait, you could fall to your death without your consent. The moves could be 1 or 2 times and the player could be alerted before to prevent cheap deaths.
Reality Crack (Passive) - Sometimes you averagely lose the grip of the real world, causing you to suffer a moderate penalty to Perception and minor hallucinations.
The small and temporal version of Schizophrenia.
Post-Threshold
Hydrocephalus (Passive) - Your head has grown and it is slightly misshapen, this makes you unable to wear any headgear except for the mouth.
Apart of deprive you of any protection for your head, this is a phase to another mutation.
Dense Cranium (Passive) - Your skull has calcified a lot, giving you more HP and slight resistance to blunt and slashing attacks, this only applies to your head.
Rapture (Active) - You manipulate the synaptic activity of lesser creatures like wildlife animals, making them friendly and follow you.
This would be limited to one creature and not effective to nether inhabitants, trying to charm another critter will release the last one, so no moose army for you 
Insanity (Active) - You alter violently the brain chemistry of a target, causing it to attack anyone nearby for a short time.
This may be kind of magical so i could be debatable if its fits the game’s theme, it could affect zombies (affecting the blob maybe?) some nether inhabitants and of course, NPCs.
These are some examples of a mind-based mutagen branch could be.