DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
waifu2x - Online/Offline tool to upscale images
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
A.I. Gigapixel - AI based image resizer
Ralpha Image Resizer - High-speed image batch conversion tool
AI Img Enlarger - Enlarge Images Without Losing Quality Online