[MENTION=85179]ren1999[/MENTION] I think one thread would be preferable, or perhaps grouping some spells together (like holds/charms here).
Ok, time to address the actual spell:
I like the HP threshold, but I suppose an alternative would be a level threshold. That's if monsters have 'levels'. It's not clear if they will have a way for DMs to figure out when a monster is appropriate a challenge or not. If they can use something simple like 'level', then resistances to certain magic could be easily expressed as 'this creature is x levels higher against these spells/effects'.
I would rather have these mind-affecting spells combined, rather than there being person/monster/everything ever types. I'd like to see the following spells presented in no particular order:
Charm - only works on something non-hostile, makes them like you, almost entirely for social interaction purposes. They won't do things they wouldn't normally do for a casual friend. They don't know they are charmed, and when it runs out they aren't aware either (other than perhaps feeling like the caster has been a bad friend, or they have been too nice today or something - repeated use might give the game away).
Calm - works on hostile creatures, allowing for social interaction or escape. They don't know they are calmed, and essentially treat the caster/allies as strangers. After it runs out they may or may not be hostile again, depending on the situation (so a calmed guard who catches you stealing would become hostile again and report you if you have escaped, but a commoner in a bar fight because you insulted his mother might leave you alone).
Frenzy - to counter Calm, they will attack anyone and anything they can. Everyone appears hostile to them, and intelligence goes out the window, so that the nearest person, or the one who last attacked them gets attacked. Powerful, so low thresholds.
Distraction - they will ignore the caster, though not his allies. Any deliberate interaction will obviously break this effect, and victims might have the nagging feeling that they are missing something. Used in combat for defence (the caster won't be attacked if they don't break the effect) or for stealth purposes (doesn't make you invisible, but will make it easier to sneak around). When it's over you won't realised you were distracted unless there are obvious consequences, such as the crown jewels are missing.
Sleep - the victim falls unconcious, but will be awoken by anything that hits them, or moves them or otherwise rouses them (seriously loud noises for instance, but not just background battle noise). Powerful, so low thresholds again.
Stun - the victim is stunned, finding it difficult to move and act, I think this is currently disadv on everything and adv on attacks on the victim.
Confusion - the victim acts randomly, everyone's favourite! They'll still defend themselves normally, but it's a toss-up whether they are calmed, frenzied or act normally.
Paralyse - this is how hold should work, paralysing the victim. It should be quite high-level (or if using thresholds, have low ones). They are unable to move or act other than mentally.
Dominate - gives the caster complete control of the victims actions, simple as that.
Whether these spells are available at all levels (with different thresholds) or later levels depends on the magic system. If they go for a spell-slot-level-determines-power system (please oh please) then I don't see a harm in them being available at all levels, albeit with different linear scalings. Effects can be ordered by power level, which is roughly Charm, Calm, Distract, Sleep, Frenzy, Stun, Confuse, Paralyse, Dominate and assigned thresholds that scale accordingly, or be available at a certain level accordingly.