DwD have published a small but highly respected set of d% games under the “Bare Bones” or D100 lite banner. They do not have a huge range, but reviewers are universally in agreement, their basic engine is solid and clean, their ideas strong and their value immense.
Their games are light hearted, but not light weight offerings, packing an enormous amount into each slim volume. These are not filler games, but neither are they a hard entry point.
I have only these two at the moment, with Covert Ops GM manual and the two Frontier Space books in my DTRPG cart.
Probably the easiest “modernised” mechanics. The d00 lite system has plenty of neat ideas to fix other games, as well as each being a good option in their own right.
My main interest here is the Frontier Space game as a more Space Opera option to M-Space (which feels more inclined towards hard sci fi) and I would love to do a Spec Ops takes on a Fae dimension intruders Dresden Files style (basically a mirror world with cross over points, kind of Men In Black for fantasy), but I will wait to see how the more detailed and made to measure Mythras “After the Vampire Wars” expansion goes.
A new gem is the Art of Wuxia. Not really on my radar, because I am not into modern Wuxia games (which I assumed it was about), I have been converted. This is the ideal tool to do any fantasy-historical game like Monkey or any of the better Manga. It can be historical with some or no supernatural or high fantasy.
Another really cool element to these systems is that, aside from Frontier Space, which uses a slightly different characteristic spread, they are all compatible to a high degree. Want to do the above mentioned Men in Black vs fantasy creatures? Just combine Fantasy and Covert Ops. Want a more Big trouble in little China feel, then Wuxia + C.O.. They even give you options in the books for good cross-over points.