So are we basically done regarding beta Pokemon leaks in the vein of the legendary SpaceWorld GS demo? We still are missing the piece of Gen 1's beta where Gorochu was made for, only seeing its back sprite IIRC.
Everything wack0 had for mainline Pokemon is out there (I have no idea about the other series and games but would assume so), so as far as seeing new designs that's finished. There's a small chance whoever leaked Gen 3 did it incorrectly like with what happened with Gen 4 at first, but that'd really be the only shot at more Pokemon designs themselves from this leak in particular.
As for other info from the Pokemon sources such as maps and remnants of builds we don't have:
Gen 1- There's occasionally minor discoveries made in the margins of files where things shouldn't be, like Red's father's sprite having been placed and then replaced by the guy who gives you Lapras in Silph Co, or partially figuring out why the Cinnabar coast glitch happens in Gen 1 (experimental change Morimoto made for Yellow that was reverted for Yellow but accidentally made its way into the RB source), but due to the actual file creation dates being wiped to 1998/3/1 there's a lot of dead ends with researching RG's development.
Gen 2- So we have the .SXY files (Structure X,Y, essentially all warps, coord events, bg events, and NPCs that a map has) for two builds that aren't out there; June 15th and July 14th (SW99 is August 17th). There's a ton of stuff in there that I couldn't cover in one post, like Burned Tower originally being an actual tower before being turned into a 3-floor dungeon with an Entei static encounter in B2F, or knowing the exact location of the Ecruteak Pharmacist, or Ice Path's original west entrance being in Blackthorn before Dragon's Den existed, or the Goldenrod Game Corner being in the Underground Path itself, but unfortunately I am literally one of two people researching these files at the moment and there's just so, so much to cover. There were also some bug testing correspondence .txts in mons2 that have also filled in a few gaps (like apparently Suicune
was physically placed somewhere in Johto but they mentioned they would be "changing its habitat" soon and this was unfortunately from May 99 so there's no info on where), but there's still a lot of things about Gen 2 to discover.
Gen 3/4- I'm focusing most of my attention on Gen 1/2 but I do know that those two generations have a few devoted researchers, one of them even found that Meteor Falls was supposed to be the dungeon with the ice cave instead of Shoal Cave at one point.
Also, don't expect the Gen 1 fronts anytime soon or at all. Even getting the backs or any of the stuff in this entire leak was a once-in-a-lifetime chance, the only way those are getting out is if Game Freak themselves release them (like was the case with the Tajiri manga and that one day Ishihara decided to show that binder) or someone manages to get their hands on the RG source, which I can imagine is multitudes harder nowadays after all of this.