I've been re-reading some AD&D rules variants I wrote years ago. It's all stuff I wouldn't do now -- far too complicated -- but there are some ideas in there that might work. But aside from being an idea mine, it's also been an opportunity think about my changing attitudes towards RPGs and towards D&D specifically.
I didn't date any of the fifty-some pages of notes in this notebook, but I know it's from a time when I was considering submitting something to The Dragon. The style of the notes are that of a very-thorough rough draft of alternate spells, character classes, and house rules. It's very clearly for AD&D (I even labeled it that way,) and is post-Unearthed Arcana, because there are references to UA ideas; my alternate character classes have 1-3 pre-first level training ranks on their experience progression charts, and there are a bunch of alternative ability scores patterned after Comeliness. However, I know these notes are pre-2nd edition, because the release of 2nd edition turned me off D&D for a while and I didn't think old 1st edition material would be of interest to anyone until the recent old school revival.
The material is much more complicated than my current approach; the alternative spells section includes traditional 1e spell blocks with range, duration, and required components for very specialized spells like Desalinate Water and Find Portal. Still, there are hints of an attempt to simply by using analogy to existing system components, such as my rewrite of the psionics rules that use the standard combat system as a model instead of the official percentile system. My general approach then still echoes in what I try to do now: look for patterns in the existing rules to inspire new variations, but pattern the new material after the old as much as possible to keep the system coherent.
I'm slightly tempted to re-vamp some of the material for OSRIC and send it to one of the old-school zines. At least then, someone might actually be able to use it.