Just some random answers, I'm a fan of DR strings. Lo riders in particular, mediun gauge 45/105. Recently switched from the nickel lo riders to the SS. As for discontinued strings, no concerns here, unless DR goes belly up which isn't likely. But if they were to go under I suppose I'd have to spend a lot of money buying as many sets as possible and sealing them all up to last. There nothing lost nothing gained.
Strings I've had a really good time with (for reference I use Ernie Ball Super Slinkys for my "average" string (Green package)):
Warwick Black Labels (or Red Labels, I forget which): super incredibly growly mid-range strings that rocked my 4 string fretless glorious master-race Warwick
DR Black Beauty strings: Partially used for aesthetic reasons, admittedly (I lucked out and got a natural satin finish corvette, ebony fingerboard), but I find they give a really nice feel for fretless. The strings become super easy to play after an hour or two, as though they feel "soft" to the touch, even though their tension is pretty usual.
D'addario Lo-riders: These things rock the hell out of my precision. A lot of clarity, keeps a good amount of growl - I love them for funking around
Ernie Ball Cobalt flats: I hand-made my own electric fretless and I love them, but I can't say a lot about the tension or feel of them. They're very "uprighty" for me, but only because the thing practically is an upright. Note that I do play upright, so I'm not complaining about it. Thick neck, wide fingerboard, custom designed for BEAD tuning (down the octave),
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Suggestions aside, what excites me most about strings is getting them. I love servicing the instrument between changes. Taking care of things is what I like to do most