Handy links to the most common methods you will likely use as a beff outfit creator:

Save Adversary

How to save items from adversary jobs (PS4 only)

Video courtesy of Lenny & Tuna

Save CEO Outfits

How to save CEO armour, red headphones & joggers

Video courtesy of XynB

Save Versus Outfits

Open interaction menu, spam illuminated clothing for 30-60 seconds, leave interaction menu open, get kicked for idling.

FIB Badge

How to get and save the FIB badge

Video courtesy of OddFutureRebel

Unlock Impotent rage

Item locations to unlock Impotent Rage outfit

Video courtesy of GTA Series Videos

Unlock alien

Item locations to unlock Space Interloper suit

Video courtesy of GTA Series Videos

@mambacrew8, @seryi_smg

How to glitch the scubasuit shoes into flippers

Video courtesy of GRAVESIGHT

Yellow Rebreather

How to get the yellow rebreather + duffel bag

Video courtesy of Mad Glitchers