Ebay or used golf club sites like 2ndswing

Finding one will be a tall order since you're looking for a club that's 20 - 22 years old...most likely places would be eBay, 2ndSwing (or any of the other used club websites) or the bargain barrel at golf stores/shops.
Best of luck to you with finding one.

E-bay has a 975F 5W listed for $40 + $16 shipping. Good luck.

If you haven't had one in the past, maybe you should consider something more recent. Even Henrik Stenson moved on from his Diablo Tour 3W (after he cracked the 3rd and last one).

I have a 975J driver and 975F 18.5 in my Dad's bag. I personally think the 913 series is the best for fairways and the driver. There are a lot of vendors for headweights on eBay. I think the 816H1 are the best hybrids. I've been using them since the beginning of 2019. I have 3 driver shafts available (Bassara S, R, A). Also have a Diamana 70 R and 72 R in reserve for the 3W and 5W. I went to Diamana S70+ stiff on the hybrids before the COVID shutdown. Been using 695MB 6-8 since Feb.