SBB has branched off into several games. These seem like the perfect things to use for Category Extentions. Theres a lot of them, and they aren't as active as the main SBB community, just like other category extensions. Here's what I think we'd use.
lolsbb - https://web.roblox.com/games/5793116018/sbb-with-lolwut-physics (basically just a slightly older, slightly different physics of SBB.)
No Barriers - https://web.roblox.com/games/6998909529/SBB-but-no-barriers (defines itself)
Insane Top Speed - https://web.roblox.com/games/6933330559/SBB-but-with-insane-top-speed (the definition of a SPEEDrun)
Now some more of the Category Extentions styled runs
Lobby% - Time starts on the first frame of movement in Slime Factory and ends the frame you touch the ground in the lobby. Don't reset.
Drag Race - Use IGT for the Drag Race in the lobby. There would be a section for all the pads (Blue, Red, Yellow, and no pad)
SFOTH% - Time starts on the first frame of movement in Shedletsky's Castle and ends the frame you hit the large tower above the spiral (staircase?) room.
As a community request, jumpless and boostless were added as full-game categories.
I added Luxtra as a moderator (since they moderate the SBB discord), and added Rube7, YT_Valentin and dankdarkel_ as verifiers to keep up with submissions.