My favourite "plain" cross-zip is the Buco JH-01:
The Langlitz cascade is pretty plain too:
Like has been said before, an Aero Bootlegger, with or without D pocket are pretty easy to wear:
The Vanson CHP2 and Chopper are also pretty plain IMO:
As are the variations of the PJ-27
Or a Schott 620/621:
![ie2J6wd.jpg](https://i.imgur.com/ie2J6wd.jpg)
![KuUR84f.jpg](https://i.imgur.com/KuUR84f.jpg)
The Langlitz cascade is pretty plain too:
![fEG8sUc.jpg](https://i.imgur.com/fEG8sUc.jpg)
![3AWoH1F.jpg](https://i.imgur.com/3AWoH1F.jpg)
Like has been said before, an Aero Bootlegger, with or without D pocket are pretty easy to wear:
![sVKPskS.jpg](https://i.imgur.com/sVKPskS.jpg)
![L0qPbJQ.jpg](https://i.imgur.com/L0qPbJQ.jpg)
The Vanson CHP2 and Chopper are also pretty plain IMO:
![ApCH3GG.jpg](https://i.imgur.com/ApCH3GG.jpg)
![OciQS2x.jpg](https://i.imgur.com/OciQS2x.jpg)
As are the variations of the PJ-27
![zNMBz1G.jpg](https://i.imgur.com/zNMBz1G.jpg)
Or a Schott 620/621:
![Vm4hVvB.jpg](https://i.imgur.com/Vm4hVvB.jpg)