Reddit mentions of Raising Electronics 1U Horizontal Rack Mount Cable Management Unit with Panel Plastic 19" Rack Mount

It's a super-cheap 1U cable management tray from Amazon :D The front panel is a little flimsy, but it works perfectly fine for shoving cables into.

Yeah I was thinking something like this 1U Horizontal Rack Mount Cable Management Unit with Panel Plastic https://www.amazon.com/dp/B0145HHLLE/ref=cm_sw_r_cp_apa_i_It1TCbSFFMPFG but I'm sure there are others

Here's what I've got in between the switches. They're entirely for cable management, and they get the job done well.

As far as Synology over Drobo, FreeNAS, or QNAP? My office purchased a Synology for a project and I fell in love with how simple it was. I couldn't really break it, no matter how hard I tried :)

Something like this would do ; Monoprice would be my goto place for cheap cables, but otherwise yea man its a good place to start.

I like the covered style, like this:

https://www.amazon.com/dp/B0145HHLLE/ref=cm_sw_r_cp_apa_DDQQzbJ8T9D0D

I like it because you can leave the cable pretty loose (therefore easy to work with and no Velcro ties needed), but it still keeps it tidy. You can get vertical versions of the same thing, which is where I put the extra slack off the cable (just let it loop down). If you have a fair amount of connections in your patch panel, consider getting one that is double sided. Obviously, it comes in a variety of sizes. Typically, 24 cables per 1u is a good guideline.

Edit: before and after. This isn't the best example for several reasons, but it gives you an idea of what good cable management can do. Some things worth noting here:

1. We removed a switch and 1/2 the cables. (Instead of having the PC and the IP phone plugged into the wall, the PCs now connect through the phone.) This will make anything look better.
   
2. No vertical management like I mentioned. It's too short and there is not a good way to attach it on this rack. This may be similar to what you have, though.
   
3. Mixed type of management. You can clearly see the ring type and covered type here. That may actually help you decide which you like better, though.
   
4. The extra slack is pushed through the holes in the back of the covered management. I don't like to do this because it makes working with the cabling more difficult, but when there is no vertical management to take care of it, it's an alright option.