....................... I did buy a few items, like the tool to make the body washers for Darrin's. Of course you can't find any flat washers that size to make any but I like interesting tools! ……………………….
You might try Fastenal's website for washers, and also bolt lengths that are between standard hardware store lengths.
I've had pretty good luck there, the filter on the left side of the page lets you choose ID, OD & thickness as well as other things, instead of just standard SAE, USS or metric washer sizes. Occasionally a metric washer is a match.
The local Fastenal used to let my orders "piggyback" on the daily shipments from their nearest supply hub (indy) but corporate changed that a few months ago & now requires a standard shipping fee on any size order that pretty much equals UPS dropping it off at my door.