We often use custom tables for this information depending on what you are looking to store. We have worked with Sitecore extensively as well and that is a very nice feature.
Also to expand on what Trevor recommends, in version 9 especially you could relatively easily create a module interface for the storing of this data. As long as you use the default forms and display methods, then you would actually have to do no coding to make this happen. Once you had the structure in place, you could do one of a few things to help you out.
You could add a UniGridView web part and use SQL to access the items in the module and display, etc.
For finer control you could build a web part that you could store in the content tree that would display a grid view (or what ever you wanted), allow paging, etc. and the edit controls to simulate the functionality of the item buckets in Sitecore
You could extend the module, add all the interfaces in there and actually integrate with the Kentico admin menu structure so it was handled more globally
Also in Kentico 9, you do have the ability to to set page types as container only. you would still see it as a structure, but these special types are just meant to store content to be accessed from other areas vs. actually having a display side like a default page type. If you can handle seeing the content tree, this would be the best and easiest way to do this.