Spotlight problems
I never liked Spotlight. In 99% of all my searches I search for files. In Spotlight I have to type the filename. Yes, I want to search files. Then I have to set the type to document so that the search does't find emails or other stuff. When I want to search in another folder then - thank you Apple - I have to start again. As developer I need to poke into areas of macOS that Apple thinks shouldn't be found by search.
A while ago I managed to lose the size attribute for searching. When I counted the possible attributes I can use for searching I ended up with over 100: way too many. Now and then I want to check what files were created or changed in the last minutes as result of using an installer. The Finder search allows only a range that is days or larger.
Find Any File Overview
Find Any File by Thomas Tempelmann makes searching simple again. And it saved my bacon more times than I can count. I'm very happy to be one of the first beta testers of FAF2. The new version will bring 64bit compatibility and speed improvements for APFS.
The interface is simple: you select where you want to search and the search field with an search operator. Then you enter a search term, you click search and you get the result.

1: Location
The first part is to select where you want to search. From everything to the main hard disk (that would be Macci here) to network volumes:
2: Search Field
You can search for the fields name, modification date, file size, labels, only folders and quite a few more. Name, modification date and file size are the search fields that I use the most.

I call those search fields the usual suspects. If you want to search the EXIF data of your photos you would do that in your photo app anyways.
3: Operator
For each search field you get a list of operators that fit to the search fields. The operators for text search fields have the usual "contains" or "ends with" operators:

But you can also do pattern matching ("matches regex" which always looks like fly spots).
The modification date search field has operators for a time range:
4: Search Term
Now enter a search term. If you add a space between the words you can search for multiple files. The help at the bottom of the screen shows this. An "or" search is done with the operators "contains either of" und "ends in either of". You can have more than one search criteria when you click on the plus button before the search field.
5: Click on the Search button
After clicking on the Search button you will need to wait a bit until you get the result in a second window:
You get a typical file result with file name, type, modified date and size. The number of results is in the lower right corner - here I found 797 files.
Above is the search result as flat list. You can also get the result as hierarchical list or a list of icons. You can change this in the upper left corner with View. Invisible files can be shown or hidden. You can do the same for packages or files in the trash. You can filter the result further by using the filter in the upper right corner of the result window.
Select a file and do a right-mouse click on the file to show the context menu:
From here you can open the selected file, delete it immediately or move it to the trash and quite a few things more.
What can you do with Find Any File:
- Search for files that can't be found by Spotlight. Files in the Library folder or the anywhere else that Apple doesn't want you to poke into.
- Use FAF as uninstallation app. Search for all files from an app and delete the files. Search for the app name with spaces and without. For instance the preferences file would be "appname" and not "app name". Don't waste your money of expensive "cleaning" tools.
- Find out what was done in the last 5 or 10 minutes. For instance, when you aren't sure what an app has installed. Or you saved a file somewhere and can't find it.
How FAF saved my sanity
When I was working with the preferences for my application Mail Archiver I had an odd effect. I saved some values to the preferences. But when reading the preferences the values weren't changed. I checked and tested and I couldn't get my code to work. Then I thought: let me check the preferences file name with Find Any File. And bingo: there was the solution. You can write preferences for the current user and for all users. I had mixed both of them up and as a result I had 2 preference files for one app. I wrote one value to "all users" and read back "current user".
Speed considerations
One fly in the ointment is that the new great APFS still is consistently slower than the old HFS file system (see the blog entry from Thomas Tempelmann for concrete numbers). A search on Catalina for a nonsense word took over 30 seconds. The MacBook Air has a 256 GB SSD hard disk with 100 GB free. On my iMac this took 6 seconds. The iMac has a fusion drive so it's not even a full SSD. The fusion drive has 1 TB with 200 GB free space.
Verdict
Find Any File is an indispensable tool for every Mac user. The only drawback: with 7 $ it costs way not enough.