>>18558702 (OP)
thats an interesting challenge!
the first obvious tip i can give you is to take note of what cuts and silhouettes return
1920s ties are the same as 1950s/60s ties
1970s shirts can easily pass for 1930s shirts
1940s jackets aren't too dissimilar to 1990s jackets, and so forth
and through the whole 20th century, many things, especially jewellery and acessories stay roughly the same, like collar bars, cufflinks, suspenders, belts, dress shoes, etc.
so... hmm
SHIRTS:
>1970s long collared shirt, patterned (40s, 70s)
>shorter point collared shirt, white (50s, 80s, )
>light blue shirt, perhaps denim even (60s, 90s)
JACKETS:
>suit jacket with wide lapels and wide shoulders (fits 40s, 70s)
>slim checked suit jacket with slim lapels (50s, 60s)
>boxy suit jacket with normal lapels (80s, 90s)
TIES:
>skinny mod tie (50s, 60s, 80s)
>wide tie with painterly design (four-in-hand knot for 40s and 90s, full windsor knot for 70s)
>normal width tie (80s)
PANTS:
>slim pants (50s, 60s)
>flared pants (70s)
>pleated pants (40s, 80s, 90s)
(go for wool or corduroy, no jeans)
SHOES:
>black penny loafers (50s, 90s)
>dark brown oxfords (40s, 80s,)
>cuban-heel zipper boots (60s, 70s)
ACESSORIES/MISC:
>belt (50s, 60s, 70s, 90s)
>suspenders (40s, 80s)
>collar clip (40s, 50s, 80s)
>sweater vest (40s, 50s, 90s,)
>loose car coat (50s, 60s, 80s, 90s)
>structured double breasted overcoat (40s, 70s)
>circular sunglasses (60s, 70s)
>ball cap (90s)
go for colors like brown, navy, and grey, it will help things go together
and i just realized this is all only up to the 90s, not to today