Hi Angela,
There is an "in" operator that you can see a use case of at the end of this blog. This example is for querying on collections of items, though I'm pretty sure it would be possible for an array of strings like you're proposing. I still need to test this myself (still getting my test instances set up), but I believe the syntax would be something like the example below:
https://beautifulplm.com/test/server/odata/MagicItemType?$filter=in(serial_number,('9879','678','643','123','234')).
Off-topic: happy to see you are back(?) christopher_gillis!
