you can find all the weapons and armor in a footlocker in the 2nd floor of the megaton player house

weapons

Absolution: can be found in the scrapyard offices once you get the contract killer perk
Insugent's chinese pistol: can be found in the drainage chamber near broadcast tower KT8
Law dog:  can be found in the police station basement  in the firing range on a table
alloy steel 10mm: can be found at flak and shrapnels
Chroma: can be found at flak and shrapnels
Backstaber: found in the plunger room on a sink
Elora: found in hamiltons hideaway in the weapons stash
slavers jury rigged AR: sold by pronto after you do his sidequest to expand his inventory
miss-mine-launcher: sold by moira brown
persica: found in the regulator office after getting the lawbringer perk
nero: found in the model home in one of the homes in minefield.
jury rigged plasma rifle: sold by durga in the citadel
jury rigged laser rifle: sold by durga in the citadel


armor
makeshift ghoul mask: found on a wastland recluse in the green pastures disposal site
infiltrators hat: sold by seagrave holmes in rivit city
raider pyro mask: sold by pronto after doing the side quest to expand his inventory
brawler's leather armor: sold by grandma sparkles