Can I suggest you stop for a moment and consider your use of Lightroom? The tool Lightroom is a library manager, and within its technical insides, the tool is database management software for the management of image files. The software will manage an unlimited number of images. My library contains 78,633 images this morning.

I don't look at all 79K. Rather, I use various filters to isolate or otherwise limit the images presented. One useful view is the "Previous Import" which is applicable until you import more images.

The next relevant view / organization is the use of "Collections". These are virtual folders and have no relation to the folder structure of the images on your disk. However, Collections are only as effective as your active placement of imported images into those collections. Being a virtual tool existing inside LR, collections can be either permanent or temporary. You might carefully organize your images in collections by subject or location, etc. You might also have a "WIP" collection you just dump images into when you plan to revisit, but just not right now. Unlike folders on disk, an image can exist in multiple collections at once. Deleting a collection does nothing to the actual image file.

As database management software, the Library Filters are frequently used tools, both in the main "All Photographs" Catalog view and within all of Collections you may create (as well as within folder views within LR). Metadata filters lets you add / remove column filters such as date, camera, aspect ratio, etc. One or several metadata filters can be combined with the Text and Attribute filters to isolate images.

So, if I want all the images from July 17, 2015, my ability to find them can include methods:

a) Metadata filter by date
b) Keyword search = Kings Island, where we happened to be (or Cincinnati or Ohio, as two other text keywords I added to the images during editing)
c) The Kings Island collection inside the Ohio collection set, again based on organization work I did when editing the images in 2015

I don't keep any images that are not complete and ready for presentation. I don't keep slightly different versions of the same thing. I don't keep out of focus misses. I don't keep unflattering views of people. Or said another way: I aggressively cull and permanently delete.

Usually, I delete in two steps. First, every image to be deleted is marked as 'rejected' with the 'x' key while the image (or group of images) are selected. When working in a collection, the 'reject' images can be removed from the collection, but the images can't be deleted from a collection. Rather, you need to view all images from the 'All Photographs' view of the Catalog. There, use the Attribute Filter and isolate those images with the 'Reject' attribute flag. In this view, you call 'select all' for the filtered Rejects and (on Windows) press <Delete> where you're presented with a dialog to remove from the catalog or remove from the catalog and delete the underlying image file.

And to "really delete" the image files, you have to empty the (Windows) recycle bin as the deleted image files are moved to the Recycle Bin by LR during the step above.

So, this is a long-winded request that you consider what you're using LR for? It is not a tool for just your current work. Rather, Lightroom should be an ever-growing library of all your digital images ever, whether you keep everything or only your finished and best work. In my view and usage of LR, you can't have too many images, just like you can't have too many book, or money, or cameras, or tomatoes ....

There are times when an image just has to be deleted.

When I import a shoot, I import all the images. They include out of focus images, images of my foot because I was holding the camera too casually, and images that my wife demands that I delete.

You can select all those images in the usual ways ( click, ctrl/cmd- click, and shift-click). If you are in the library grid mode (keyboard shortcut g), pressing delete will allow you to delete all the selections from the catalog or the disk. Outside of the library grid mode pressing delete will only act on the primary selection.

I keep all the reasonable images and use collections and color labels to organize them.