I have a 3-tier drawer storage like this - https://www.target.com/p/sterilite-three-drawer-wide-cart-white-with-clear-drawers/-/A-13981330 - except mine doesn't have wheels, and with keeping heavier things in the bottom, it doesn't open up or slide around. I keep all of my "kitchen" stuff and hygiene stuff in there.
My other "shelving" is a single shelf I have underneath a 5 foot table/workbench along the side, and I just use a trunk cargo net like this - https://www.amazon.com/dp/B00XKKHAZU - and it works great. I use this shelf for my different bags - I don't really have many "loose" objects. I have a beach bag, a gym bag, an "outdoor" bag (for hiking/camping stuff), and a "recreation" bag that holds thinks like my basketball, tennis racket/balls, hockey pucks/balls, inline skates, and frisbies. I don't have to worry about things rolling around, and it makes it super easy to just grab a bag and go - depending on what I'm trying to do.
The rest of my storage is just under my bed, either in a milk crate which has my van-related stuff like tools, etc., or duffel bags that have other things like my clothes, etc. I keep my portable shower pump and solar shower in a 5 gallon bucket.
The only thing that is fastened at all in my van is my bed and my side table/workbench. I have zero issues with things sliding around.