I am playing a Kenku shadow monk 7 efretti warlock 3 and I was wondering which pact boon I should choose. His main weapons are a handaxe, a javelin and a laser rifle. Thanks in advance for your suggestions

I would suggest going with Pact of the Chain and taking one of the extra familiar choices, because familiars are always handy, especially when they can turn invisible.

Pact of the blade might also be good for you if you take Improved Pact Weapon for one of your invocations. It would allow you to summon a +1 monk weapon that can be used as an arcane focus for your spells.

Pact of the Talisman might be useful, depending on your role in the party.

You probably won't need the extra cantrips from Pact of Tome, so I'd steer clear unless you really want the ritual spells from the Book of Ancient Secrets invocation.

Pact of the Chain is probably the best:
You can forgo one of your attacks to have it attack.  You have plenty and it might do different things.
Its a great scout.
It is the most useful without spending additional invocations leaving you to keep your current invocations.
HOWEVER
if you want to spend an invocation, Gift of the Ever Loving Ones, Investment of the Chain Master, Voice of the Chain Master are all available and great.

Finally, your familiar can carry around your genie bottle.  Always great.

Quote from Elfdope >>

Finally, your familiar can carry around your genie bottle.  Always great.

  Never considered using it like this. An imp carrying a genie bottle could transport your whole party through an area while invisible. Sneaky sneaky!

You had me at invisible raven carrying a bottle

(imp shape change into raven, turn invisible)

I think generally speaking the best Pact Boon is Pact of the Blade because if you put enough Eldritch Invocations into it it basically becomes better than a lot of very rare and sometimes legendary weapons

Also, smiting from 600 ft away is super fun

The reason It wasn’t an instant Blade for me is that you can’t summon guns with it and I heavily use a laser rifle