I have a large number o fcustom blocks created. When I make a new block and wanted to add it to a custom page, I use to find the new block at the bottom of the list of available blocks.
 
Lately this has not been happening and I find that the new block could be anywhere in the block list, making it very time consuming to scroll through all of the blocks.
 
In the page layout, there is no ability to search for a block.
 
Is there some way to sort these so the new blocks are on the bottom or top, or even sort by alpha,

I see what you mean. I just looked in a custom category layout page, and the available custom blocks seem to be in a random order. If they were either alphabetic or by ID number they would be much easier to find.