I was going to be ruthless about throwing out the ones that didn't work anymore, but some of the ancient and venerable have sentimental value, or are promo pens in a barrel style that I find very comfortable to use, so I set about investigating the availability of refills.
First port of call was the Cult Pens website, a wondrous cavern of everything pen. It turned out they were having a three for two special deal on Schneider products, and Schneider make All the Refills, or pretty close to it. I already had a Schneider disposable courtesy of a sample in a previous order, so I knew they made decent cheap pens. Cue buying binge…
I needed a selection of refills, and I haven't had a chance to do much with most of them yet, but so far -- nice refills. They write smoothly and don't need much pressure to get them started. I really like the Slider 755, which is a Parker style G2 filled with Schneider's ViscoGlide hybrid ink. It writes very smoothly with no skipping and almost no pressure once it gets going, but can write on gloss paper without smearing even if it gets wet. It's described as combining the best features of ballpoint and gel pens. It's moderately expensive but I think well worth it if it continues to perform like this. I do love my fountain pens for not needing any pressure to write, but this refill comes close and is waterproof to boot.
The refills are all clearly labelled with brand, model number, colour and tip size, even the tiny D1 format multipen refills. This might not sound important, but when you've just opened an envelope full of miscellaneous loose refills, it's very useful for matching refill to pen. Definitely for my "buy again" list.
You can find the Schneider range in lots of pen shops, and as of the time of writing there is still a three for two offer at Cult Pens for the entire range.