#and all the really damn obscure faction paradox stuff

[gen-is-gone]

listen if I had a time machine and access to various collectibles, why in earth do you think I would sell them? I want that shit for me

Seriously, the easiest way for a time-traveler to make present-day money completely untraceably would be comicbooks.

Go buy yourself a US 10c coin from 1935, which will apparently set you back around $8.50; set your time machine for New York, April 18th 1938; walk up to a newsstand and buy a copy of Action Comics #1 with your dime.

Come back to the present, send the comic off to be professionally graded, tell everyone you found it in a yard sale, sell it at auction, and congratulations: your $8.50 is now $3.25 million.

Repeat with Detective Comics #27, Amazing Fantasy #15, etc.

Hell, if you don't wanna draw attention to yourself, just pick less expensive comics! Need $600 quick? Go to February 1991, pick up New Mutants #98 for a dollar, and a Deadpool fan will take that off your hands really quick.

Comics are mass-produced, so history won't miss a copy or two going missing; basically untraceable once sold; and can easily be claimed as something you found in a yard sale or charity shop.