Some simple categories of apps that can't realistically exist on the iOS/iPadOS/visionOS App Store off the top of my head (there will be rare, hoop-jumping exceptions, of course):
• Virtualization tools & VMs
• Emulators or language runtimes that require JIT
• Compilers & IDEs that can deploy locally
• Disk management tools
• Backup and recovery software
• Screen sharing & remote control
• Any software with a plugin model for extensibility (like most pro apps)
• System shell replacements