Assuming they haven't discontinued them, Northshore also has (or had) their GoSupreme Lite underwear. It's similar to the GoSupreme, but thinner and less absorbent, but still crazy thick compared to just about any other pull-on you might find. I have a couple samples laying around. Definitely quite thick. Not sure how much they absorb, or how much they cost, but...certainly less than the full-absorbency version.
Northshore also has FlexSupreme, but I've heard very few good things about it. It generally seems to be regarded as an inferior product to GoSupreme, but if it fits and does the job for you, and is more affordable (I'm pretty sure it's priced significantly lower), then by all means. They might have discontinued it, though, not sure.
There's also Abena Abri-Flex (currently being rebranded to Abena Pants in the US and possibly elsewhere; supposedly the product itself hasn't changed, aside from the print, but...we'll see). It's available in four different absorbencies, from 0 to 3. Supposedly even 0 is thick (compared to other pull-ons) and will still far outdo what you find on the shelf at a store. I have M3 for medium, in the highest absorbency available, but again, I haven't used it yet. My IC issues are are thankfully not flaring up at the moment, and I also have yet to find any free time to, uhhh...test them. Abri-Flex M3 is right up there with GoSupreme for absorbency. I will say the M3 is kind of pricey (some places have much better pricing than others, so look around; I think J and B At Home and Vitality Medical had some of the better prices that I've found), though buying by the case definitely takes the sting off a bit. I picked up two packs to try, and it was painful.
As mentioned above, the Tranquility Premium Overnight Underwear is generally quite well-liked, and seems to be regarded as a decent budget alternative to Northshore GoSupreme and Abena. It's obviously not as good as those, but again, seems to blow a lot of the other offerings out of the water. They're one of the things I'd like to try next.
Like you, I'm also hoping to find something reasonably absorbent that's affordable. I have plenty of tabbed diapers, but for wearing outside the house, I'd prefer a pull-on, if I can find one that meets my needs. I know full well that's a big if, though.
Oh! Always Discreet Boutique is also well-liked and surprisingly absorbent, if you can tolerate the obnoxious floral scent, color, and print. It's basically the core of a Pampers diaper (Baby Dry, I think I've seen people say), attached to adult-sized underwear. I've used that one personally, when I had nothing else available, and did end up having an accident, pretty much completely emptying my bladder, which it held really well. My accident was definitely a flood and not a slow leak, and I did not expect it to hold, but it did. I should say that it probably wasn't quite a full bladder, but...once I realized that it was too late and I was already going, I didn't try to stop it. I didn't push any extra out, but it emptied for a solid ten seconds straight, until I no longer felt any urge. That happened standing up, though. The main absorbent section of its pad stops pretty low in the rear, though it has really good coverage in the front (to the point that I'm inclined to say they also had male anatomy in mind). Unlike many adult underwear products, it does actually have a marginally absorbent section that does run quite far up the rear, but that part doesn't hold much at all. Basically, it's almost all SAP back there, and virtually no fluff. I wouldn't want to use it lying down. At the time I was using that (something like the end of 2020, maybe), they did have issues with the leak guards... They're folded over the elastic and then welded shut over top of it to capture the elastic, and they'd overdone it with the welder, melting a bunch of holes in the leak guards, but it didn't actually cause any major leaks. They also did have double leak guards, as I recall, which is crazy for a store-bought product. That's probably what kept them from leaking. I will say that at least one set of the leak guards (probably the outer of the two), if I recall, were made from the plastic backing that's under the outer cloth, so I did get a lot of sweat buildup along the leak guards. I think the design has changed a bit since I last used them, so I can't speak to the current design, but it was really good back then, aside from the awful smell. If it weren't for that smell and being far more feminine than I'd care for, I could happily wear those 24/7, and feel pretty well protected.
