Well, there are a few like Valhalla, Tone Boosters, Audifex. Most that are already below $100 and have no online authorization or dongle/ card authorization and or a windows service constantly running.
Vendors like UAD, Waves, SSL, Plug-in Alliance, Softube, Powercore, IK....It simply has to be on sale or a used license here or the money stays in the wallet.
Same for soundsets and synths for the most part, so far everything I have is either buy one get one free or reduced. If I were to pay full price for something, it would be sounds and I must admit I'm getting a hankering for that Omnisphere all of a sudden after hearing some demos...