Here is a Very Specific Object. For one of the nine people in the world who own a Pilot Down Force pen (I already excluded myself from the total), here’s a direct fit replacement clip for when yours breaks.
Who cares, and why? Well, part of this pen’s deal is that the clip is absolutely required to use it. That’s because the angled rib on the clip is part of the hold-open mechanism. No clip, no write.
And now, no problem.
https://www.printables.com/model/768071-pilot-down-force-replacement-clip
In addition to not being cheap, it’s also not disposable. Pilot manufactures and sells refill cartridges - you can get them in office supply stores, on Amazon, at Walmart, and at dedicated pen retailers. And it took me all of two seconds to discover that with a simple web search.