I know it's obsolete and not even sold anymore, but I really liked "Electronics Workbench" in the late 90s and early 0s or so. Unfortunately, what was a fast, small, affordable simulator was bought by NI and became the sluggish, heavily overprotected and insanely expensive NI-Multisim. For some time, there were free versions of this first from Analog Devices and later on from Mouser ("MultiSim Blue"). I used both versions for a while despite the terrible license server crap, but after some time and without prior notice, the licenses were withdrawn. So from one day to the other you couldn't even start the application or open your projects anymore. Actually even in MultiSim Blue, you couldn't open the projects created with the previous AD version of MultiSim since opening projects created with these free versions was always only possible with the very same free version of the full commercial versions.
Anyway, following the cloud/web based trends of the last years, there seems to be web based version of multisim now:
https://www.multisim.com/The page says "sign up for free" but I'm sure there's a catch and/or severe limitations if that is supposed to mean you can also use it for free to some degree. I mean, signing up is free for sure, but what does that even mean?
So anyway, even if LTSpice's GUI drives me crazy and it can be hard to impossible to get some non-LT (or even old LT) parts to run, I moved to LTSpice some years ago just because it's the only thing that you can somehow rely on to be able to open your projects in a few years from now. And well, since Analog bought LT, there are even some AD parts there.