There's no objectively "best" choice to take, you have to decide which one is best *for your character*. It'll be a combination of 3 factors:
* What you want to play
*What you think helps the party most
*What you think fits your character's story the best
How you balance those three things is up to you.
Uhh... OK... I want it to Play a small robotic, warlock that is good mainly OUTSIDE of battle, making EVERYONE their (the Characters) friend, and in battle, someone ELSE does the dirty work....
Pact of the Blade is only for people that plan to use a weapon. If you plan to use Eldritch Blast instead of using a weapon, don't bother with Pact of the Blade.
Pact of the Chain gives you a better familiar than the standard Find Familiar spell, but that's about it. Unless you really like the idea of centering your character around your familiar, don't bother with Pact of the Chain.
Pact of the Tome gives you three cantrips from any classes of your choice, and it gives you the option of choosing the Book of Ancient Secrets as an invocation. This is most likely what you should choose.
Since you have Eldritch Blast, don't bother choosing attack cantrips from other classes' spell lists. Go and choose some great utility cantrips that you think you'll enjoy. And choose the Book of Ancient Secrets Invocation (you'll have to drop one of your current invocations, but it's probably worth it) and start acquiring Ritual Spells.
Extra options for your familiar: Imp Pseudodragon Quasit Sprite It's important to note that some of these familiars have the shapechanging ability or the ability to cast invisibility on themselves at will. Invisibility + flying is a powerful combination for a scout.
Pact of the Chain can forego one of their attacks to let their Familiar attack instead.
Almost everything else about the Find Familiar spell can also be done by Pact of the Tome Warlocks that take the Book of Ancient Secrets invocation and add Find Familiar to their spell book.
Edit: Pact of the Chain gets access to an invocation that gives them unlimited range on their telepathic bond with the Familiar, whereas everyone else is limited to a 100ft range. And with this invocation you can talk through your familiar, whereas nobody else gets this ability.
Pact of the Chain also gives you access to a couple of other Invocations:
Gift of the Ever Living Ones is available to Chain Pact Warlocks of any level. With this invocation, if your familiar is within 100 feet of you, any time you regain hit points, any dice you roll to determine the number of hit points regained are maximized. This would include dice from healing spells, healing potions, or simply hit dice rolled during a short rest. The value of maximized healing can't be understated. Too bad it only affects yourself.
Chains of Carceri is available to Chain Pact Warlocks of 15th level and up. It allows you to cast Hold Monster at will, without using a spell slot, but only against celestials, elementals, and fiends. This is a highly situational invocation, but when it comes up, it's extremely useful.
Also you can cast Touch spells through your Familliar.
This can be usefull, turn the bugger invisible, make him go behind someone, and cast Shocking grasp(if you have it) or any other spell with a range of Touch, with advantage since you're invisible.
Rollback Post to RevisionRollBack
"Normality is but an Illusion, Whats normal to the Spider, is only madness for the Fly"
Also you can cast Touch spells through your Familliar.
This can be usefull, turn the bugger invisible, make him go behind someone, and cast Shocking grasp(if you have it) or any other spell with a range of Touch, with advantage since you're invisible.
This would be a lot more useful if there were more touch spells on the Warlock spell list. Plane Shift is nasty, but it's 7th level, and requires both a touch attack and a saving throw. The only other touch spell native to the Warlock list (AFAIK) is Bestow Curse, which requires one of those ridiculous "spell lost + long rest to recast" Invocations. Still, having an invisible familiar like an Imp or Sprite to cast this spell once per day almost makes the Invocation worth taking.
Aside from those two, you'd have to multiclass or take feats that grant spells (mostly cantrips) to find any other touch spells to use this ability.
Well maybe its me, but if you don't MC or use feats, i don't see why bother playing at all, but thats a personal preference.
I always take the Spell sniper(Sorceror) feat, the ignore covers and double the range of all your ranged spells is quite good.
And shocking grasp, having the Imp use shocking grasp on enemies while been invisible is hilarious.
Now there's also the case of a Celestial Warlock, been able to use Cure wounds, revivify and Lesser/great resto, without you having the need to be next to the target or if the target is too far for you/you cannot reach it, with the Imp going around invisible( so enemies cannot prevent him for doing it), is something major.
Rollback Post to RevisionRollBack
"Normality is but an Illusion, Whats normal to the Spider, is only madness for the Fly"
Pact of the Blade is only for people that plan to use a weapon. If you plan to use Eldritch Blast instead of using a weapon, don't bother with Pact of the Blade.
Pact of the Chain gives you a better familiar than the standard Find Familiar spell, but that's about it. Unless you really like the idea of centering your character around your familiar, don't bother with Pact of the Chain.
Pact of the Tome gives you three cantrips from any classes of your choice, and it gives you the option of choosing the Book of Ancient Secrets as an invocation. This is most likely what you should choose.
Since you have Eldritch Blast, don't bother choosing attack cantrips from other classes' spell lists. Go and choose some great utility cantrips that you think you'll enjoy. And choose the Book of Ancient Secrets Invocation (you'll have to drop one of your current invocations, but it's probably worth it) and start acquiring Ritual Spells.
Pact of the Chain Sounds nice, but can you describe the familiars?
Find Familiar
Extra options for your familiar:
Imp
Pseudodragon
Quasit
Sprite
It's important to note that some of these familiars have the shapechanging ability or the ability to cast invisibility on themselves at will. Invisibility + flying is a powerful combination for a scout.
Pact of the Chain can forego one of their attacks to let their Familiar attack instead.
Almost everything else about the Find Familiar spell can also be done by Pact of the Tome Warlocks that take the Book of Ancient Secrets invocation and add Find Familiar to their spell book.
Edit: Pact of the Chain gets access to an invocation that gives them unlimited range on their telepathic bond with the Familiar, whereas everyone else is limited to a 100ft range. And with this invocation you can talk through your familiar, whereas nobody else gets this ability.
Pact of the Chain also gives you access to a couple of other Invocations:
Gift of the Ever Living Ones is available to Chain Pact Warlocks of any level. With this invocation, if your familiar is within 100 feet of you, any time you regain hit points, any dice you roll to determine the number of hit points regained are maximized. This would include dice from healing spells, healing potions, or simply hit dice rolled during a short rest. The value of maximized healing can't be understated. Too bad it only affects yourself.
Chains of Carceri is available to Chain Pact Warlocks of 15th level and up. It allows you to cast Hold Monster at will, without using a spell slot, but only against celestials, elementals, and fiends. This is a highly situational invocation, but when it comes up, it's extremely useful.
DICE FALL, EVERYONE ROCKS!
Also you can cast Touch spells through your Familliar.
This can be usefull, turn the bugger invisible, make him go behind someone, and cast Shocking grasp(if you have it) or any other spell with a range of Touch, with advantage since you're invisible.
"Normality is but an Illusion, Whats normal to the Spider, is only madness for the Fly"
Kain de Frostberg- Dark Knight - (Vengeance Pal3/ Hexblade 9), Port Mourn
Kain de Draakberg-Dark Knight lvl8-Avergreen(DitA)
This would be a lot more useful if there were more touch spells on the Warlock spell list. Plane Shift is nasty, but it's 7th level, and requires both a touch attack and a saving throw. The only other touch spell native to the Warlock list (AFAIK) is Bestow Curse, which requires one of those ridiculous "spell lost + long rest to recast" Invocations. Still, having an invisible familiar like an Imp or Sprite to cast this spell once per day almost makes the Invocation worth taking.
Aside from those two, you'd have to multiclass or take feats that grant spells (mostly cantrips) to find any other touch spells to use this ability.
DICE FALL, EVERYONE ROCKS!
Well maybe its me, but if you don't MC or use feats, i don't see why bother playing at all, but thats a personal preference.
I always take the Spell sniper(Sorceror) feat, the ignore covers and double the range of all your ranged spells is quite good.
And shocking grasp, having the Imp use shocking grasp on enemies while been invisible is hilarious.
Now there's also the case of a Celestial Warlock, been able to use Cure wounds, revivify and Lesser/great resto, without you having the need to be next to the target or if the target is too far for you/you cannot reach it, with the Imp going around invisible( so enemies cannot prevent him for doing it), is something major.
"Normality is but an Illusion, Whats normal to the Spider, is only madness for the Fly"
Kain de Frostberg- Dark Knight - (Vengeance Pal3/ Hexblade 9), Port Mourn
Kain de Draakberg-Dark Knight lvl8-Avergreen(DitA)