Finished up the workbench. Made with mostly free 2x4s, with some extra 2x6s purchased.
Half laps everywhere.
Two sjoberg vises because I just have too much money to spend.
Dog holes.
Flip down casters.
Adjustable leveling feet that I designed and 3D printed. You can kick them over with your toe to adjust and get rid whatever wobble appears in that particular spot.
The diagonal brace is likely overkill and will get in the way of accessing the underside or a shelf should you choose to put one in. The whole bench will likely slide along the floor before it racks should you push hard enough.
Just writing so that other bench builders make that consideration not to shit on your project.
A shelf is a bad idea in a bench - you need easy access to the bottom to adjust clamps all the time. Now an assembly table can benefit from shelves and such - but they don't need the strength this has.
You should be wary of giving universal "bad idea" advice for under bench storage. I have a split top Rubou with a cabinet underneath that's worked great for over ten years now. There's enough room between the top of the cabinet and bottom of the bench top to let in a clamp head.