I'm a little surprised noone mentioned Google
sheets or something
that's cloud native? Probably only accessible from newer systems though
but I've debated it since it would be instantly accessible from phone
also.
Sheets is a spreadsheet program, right? Spreadsheets, while nice for keeping inventory,
aren't great for searching and organizing. For parts and inventory you really need a
DB so you can get a list of all of your EISA cards, or all of your 8-bit ISA NICs, etc.
One of the best programs (and by far the easiest) that I ever used was File Maker Pro. It
had a WYSIWIG design paradigm so you would lay out your form/input sheet/whatever using
whatever object you needed - say a drop down box. You would then use the same design to
input data and to search.
The benefit of setting up a SQL DB is that it can run on a modern server but can have a
very simple text interface for searches and editing delivered through a client or plain
text web site (running on the same server). As long as you are not getting fancy with your
"output" page even Lynx can be used to search and edit the DB.