Where can I find items with +INT in Fallout 4?

Solution 1:

The regular Lab Coat (+2 INT) can be found in the following locations:

• Anne Hargraves sells one if she is assigned to a clothing store.
• A lab coat can be obtained if one is given the lab assistant job during the Cambridge Polymer Labs quest.
• Patricia Montgomery at Covenant wears one.
• Tinker Tom sells an armored lab coat.
• Doc Crocker's lab coat can be looted from his body after the quest The Disappearing Act.
• Worn by Doc Carrington and T.S. Wallace.
• Doctor Sun and Doc Weathers wear one.
• Worn by Doctor Amari in Memory Den.
• Worn by Miranda Song at Vault 81.
• (Far Harbor DLC) Teddy Wright wears a lab coat.
  The Institute lab coat variants, the Vault-Tec lab coat, Father's lab coat, and Cabot's lab coat also give a +2 INT bonus.

The glasses you are referring to are Liam's glasses (+2 INT, -1 CHA), and can be found during:

the quest Plugging a Leak, given by Justin Ayo at the Institute, available after Mankind - Redefined. You must side with Liam in framing Justin, and pass the speech check for additional rewards to obtain the glasses.
Be aware that this quest will be unavailable if you have completed Tradecraft, which is an early quest, making these easily missed.

Other items that give an Intelligence bonus:

• Permanent effect:

  • Bobblehead: Intelligence, INT +1 ("In the northwest room of the Boston Public Library sitting on a control").
  • Perk: Night Person, +2 / +3 INT (between 6 PM and 6 AM).
  • Construction: Overseer's Desk, +1 INT (Vault-Tec Workshop DLC, limited)
  • Level: S.P.E.C.I.A.L. ability, +1 INT / level (up to 10, opting for a S.P.E.C.I.A.L. bonus instead of a perk)

• Semi-permanent effect:

  • Outfit: Destroyer's Helmet, +1 INT ("sold by Penny Fitzgerald in Covenant").
  • Outfit: Institute Division Head coat variants, +1 INT.
  • Outfit: Mechanic jumpsuit variants, +1 INT.
  • Outfit: Fancy suit & tie, +1 INT (Nuka World DLC).
  • Outfit: Acadia's Shield, +1 INT (Far Harbor DLC: "Given by DiMA if The Way Life Should Be quest is completed in his favor").
  • Headwear: The Captain's Hat, +2 INT (Far Harbor DLC).
  • Headwear: Inquisitor's Cowl, +1 INT (Far Harbor DLC).
  • Headwear: Mechanist's Helmet, +1 INT (Automatron DLC).
  • Headwear: Press cap, +1 INT.
  • Headwear: Tinker headgear, +1 INT.
  • Headgear: Ushanka hat, +1 INT.
  • Glasses: Road goggles, +1 INT.
  • Weapon: Legendary 'Sharp' effect, +1 INT.

• Temporary effect:

  • Consumable: Berry Mentats, +5 INT.
  • Consumable: Daddy-O, +3 INT.
  • Consumable: Mentats, +2 INT.
  • Consumable: X-Cell, +2 INT.

Solution 2:

I found out that you can get a +2 int lab coat from the quest "The Dissappearing Act". It's on the body of one of the doctor at the end. You get the quest by picking up the case file in Nick Valentine's office.

As mentioned by z ' you get get +1 int from pipers cap. You can take it from her inventory without stealing if she is your companion.

I don't yet know if there is any specific place you can get glasses with +int.

Apart from that there seems to be lots of +int gear on random drops as mentioned by several users (Ben Schism kalina).