Setting aside the world peace concept, and the education debate, I would like to actually address the technology aspect of the OP using D&D options.
First off, lets ignore limit-per-day options like
Sending and
Teleport spells. These would aid communication and travel, but the daily limits would supply the masses.
And so, I would first look to Stronghold Builders Guide, Wondrous Architecture (an alternative application of the Craft Wondrous Items feat), as @
kitcik has already mentioned one. To make any of these requires money, time and the appropriate spells and so would be difficult for one individual to produce, but a guild who specialized in crafting and selling these designs would likely end up both wealthy and powerful.
Some useful options include:
-Bed of Regeneration: lying on the bed
Regenerates missing limbs and heals HP. With the severed limbs in place, they reattach in 4 rounds. If growing new ones, they regrow in 2d10+3 rounds, or a max of 2 and a half minutes.
-Bed of Wellness: Comes in 3 versions. Cast's
Remove Blindness/Deafness, or
Remove Curse or
Remove Disease if you lay on it for 18 seconds.
-Bier of Life: Stone platform casts
Raise Dead on an up to 9 day old corpse if you also place a diamond worth 500gp.
-Bier of Resurrection: As Bier of Life, only 90 day of Corpse and the stone slab casts a
Resurrection spell.
-Cabinet of Stasis: Any creature put inside is in a suspended animation as the
Temporal Stasis spell, creature experiences only 1 day of aging for every decade that passes. Creature can only be removed by someone else, cannot wake self. Perhaps Craft a Contingency
Dimensional Step or something to remove a contained creature after a predetermined trigger.
-Chamber of Comfort: tempurature is always a comfy 70 degrees, Fresh air is magically circulated, any fires lit dissipates smoke into the ceiling.
-Chamber of Speed: continuous
Haste effect on anyone within room. Activities take half the time to do.
-Everful Basin: Always has 6 gallons of water.
-Everful Larder: Every time it's opened, produces enough food for 5 people. Close and reopen and get more. (rename Everful Fridge!)
-Hall of Speech: Understand all languages spoken within the room.
-Invisible Helper: Permanent
Unseen Servant within a room.
-Cloudgathering Orb, Hurricane's Eye, Orb of Pleasant Breezes: Three different Wondrous Architecture. Produces either nasty precipitation appropriate for the season, hurricane force winds, or pleasant and mild weather within a 2 mile radius.
-Platform of Greater Jaunting: a Limitless range
Dimensional Door spell, allowing to to teleport anywhere on the same plane, requiring only a reliable description of the destination to arrive successfully. (one could imagine the usefulness of a series of these!)
-Platform of Heal: stepping upon the 10' diameter square casts
Heal. multiple stepping results in endless casting of the spell.
-Platform of Levitation: ability to
Levitate up or down at a speed of 20', serves as a magical elevator.
-Pool of Greater Scrying: Limitless
Scrying spell, plus ability to cast spells upon the scryed subject.
-Stable of Understanding: A continuous
Speak With Animals effect within the room.
-Table of Feasting: a table that produces a
Heroes Feast three times a day for up to 12 people.
-Tree of Greater Jaunting: Permanent
Tree Stride at any range on the same plane. (A more classy Platform of Greater Jaunting)
And that's just from one book! Some other technological marvels might include:
-
Glowing Orb spell from Spell Compendium produces an at-will controlled permanent glass light bulb.
-Ring Gates from DMG have a 100 mile range and while they have a limit to the amount of objects passed through in a day, speaking through, flashing lights, morse code-like sounds… any method of passing information could be done endlessly across great distances. I can imagine rooms of Gnome operators communicating telegraph-style messages in information network relay stations.
…I’ll add to this list as I think of more.