In this guide you'll find required materials for every craftable outfits (Including DLC contents) & how to obtain the outfit blueprints. Some outfits require you to complete certain quests in the DLCs which can be checked at the redirects available on those outfits.

Due to the enormous amount of outfits (70 to be exact), they're divided into five parts for convenience.

For finding materials you're looking for, you can take a look at this material drop list[docs.google.com] by RalleYTN (The mob levels are in Extreme difficulty which got increased by 70 levels).

Available from the beginning.
Available from the beginning.
Complete Hunting Quest: Bounty Hunting 101.
Complete Hunting Quest: A Numbers Game.
Available from the beginning.
Available from the beginning.
Complete Main Quest: Forgotten Woods.
Complete Main Quest: Forgotten Woods.
Complete Hunting Quest: Might of the Cosmos.
Complete Hunting Quest: Identity Crisis.
Complete Hunting Quest: One in the Chamber.
Complete Hunting Quest: Every Dog Has His Day.
Complete Hunting Quest: Candy Party.
Complete Hunting Quest: Solemn Atonement.

Complete Hunting Quest: A Demon's Gaze.
Complete Hunting Quest: A Nighttime Stroll.
Complete Hunting Quest: Riding Numeric Waves.
Complete Hunting Quest: Light and Shadow.
Complete Treasure Quest: In-Game Currency? .
Complete Treasure Quest: In-Game Currency? .
Complete Hunting Quest: Candy Party.
Complete Hunting Quest: Bathed in Moonlight.
Complete Treasure Quest: Dead Riner (Must complete other Treasure Quests first).
Complete Treasure Quest: Vimod Luck Charm.
Complete Hunting Quest: A Dance in Twilight.
Complete Hunting Quest: VR Art Imitating Life.
Complete Hunting Quest: The Weight of Living.
Complete Hunting Quest: Glory Beyond the Veil.

Complete Treasure Quest: Scorched Legal Tender.
Complete Treasure Quest: Fallen Remains.
Complete Treasure Quest: Virtual Paleontology.
Complete Treasure Quest: Sake's Holy Grail.
Complete Treasure Quest: Sake's Holy Grail.
Complete Treasure Quest: Pending Towelpocalypse.
Complete Treasure Quest: Space Shroom Stuffing.
Complete Treasure Quest: Look at this Photograph.
Complete Hunting Quest: The Meaning of Justice.
Complete Hunting Quest: You Are Already Dead.
Complete Hunting Quest: A World Laid to Waste.
Complete Hunting Quest: Glory Beyond the Veil.
Complete Main Quest: Homecoming.
Complete Main Quest: Homecoming.

Complete Sub Quest: Lisbeth's Request (Requires DLC 1 Ambush of the Imposters).
Complete Sub Quest: Klein's Request (Requires DLC 1 Ambush of the Imposters).
Complete Sub Quest: Silica's Request (Requires DLC 1 Ambush of the Imposters).
Complete Klein's affinity level 2 event, then talk to him at Kirito's room.
Complete Klein's affinity level 2 event, then talk to him at Kirito's room.
Complete Sub Quest: Yuuki's Request (Requires DLC 2 Betrayal of Comrades).
Complete Sub Quest: Sinon's Request (Requires DLC 2 Betrayal of Comrades).
Complete Sub Quest: Philia's Request (Requires DLC 2 Betrayal of Comrades).
Complete Sub Quest: Strea's Request (Requires DLC 2 Betrayal of Comrades).
Complete Main Quest: Caring on Lievre (Requires DLC 3 Collapse of Balance).
Complete Sub Quest: Alice's Request (Requires DLC 3 Collapse of Balance).
Complete Sub Quest: Eugeo's Request (Requires DLC 3 Collapse of Balance).
Complete Main Quest: Lievre Assault Prep: Easy (Requires DLC 3 Collapse of Balance).
Complete Main Quest: Lievre Assault Prep: Hard (Requires DLC 3 Collapse of Balance).

Complete Main Quest: Material Gathering Request (Requires Dissonance of the Nexus expansion).
Complete Sub Quest: Material Gathering Request - 2 (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Outerwear Materials: Easy (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Outerwear Materials: Hard (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Yuna's Request (Requires Dissonance of the Nexus expansion).
Complete Sub Quest: Yuna's Request 2 (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Manhunt: Easy (Requires Dissonance of the Nexus expansion).Complete Main Quest: Manhunt: Hard (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Can't Scare Me! (Requires Dissonance of the Nexus expansion).
Complete Main Quest: Can't Scare Me! (Requires Dissonance of the Nexus expansion).
Complete Sub Quest: Still Can't Scare Me! (Requires Dissonance of the Nexus expansion).
Complete Sub Quest: Still Can't Scare Me! (Requires Dissonance of the Nexus expansion).
Complete Hidden Event from Argo (Requires Dissonance of the Nexus expansion).
Complete Hidden Event from Argo (Requires Dissonance of the Nexus expansion).

I hope that this guide can be helpful to find wanted outfit designs / required materials. If you've a question, drop a comment below. Courtesy of Anh Hoàng for allowing me to redirect his guides.

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2158457482
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2161007528