My current Apps in the macOS App Store:

• Audio-Splitter
  A simple App to split audio-files by Time, Size, Count and Time-Intercept. The supported files are mp3 and m4a.

  

• Video-Splitter
  A simple App to split video-files by Time, Time-Intercept, Count, and Size. The supported files are mp4, m4v and mov.

  

• Icon-Maker
  A simple app to resize iOS and macOS icons and create asset catalogs for Xcode.

  

• Rename-Files
  A simple app to rename files and folders (without subfolders). A preview of the renaming is also available.

  

• Regex-Coach
  A simple app to test your regualar expression for "Match" or "Replace".