Emu8086 is described as 'Microprocessor Emulator with integrated 8086 Assembler and Free Tutorial. Emulator runs programs on a Virtual Machine, it emulates real hardware, such as screen, memory and input/output devices' and is an app in the Education & Reference category. There are five alternatives to Emu8086 for Windows, Linux, Mac and Wine. The best alternative is PCem, which is both free and Open Source. Other great apps like Emu8086 are NASM (Free, Open Source), flat assembler (Free, Open Source), 86Box (Free, Open Source) and pcemu (Free).
The Netwide Assembler, NASM, is an 80x86 and x86-64 assembler designed for portability and modularity. It supports a range of object file formats, including Linux and *BSD a.out, ELF, COFF, Mach-O, Microsoft 16-bit OBJ, Win32 and Win64. It will also output plain binary files.
86Box is a hypervisor and IBM PC system emulator that specializes in running old operating systems and software designed for IBM PC systems and compatibles from 1981 through fairly recent system designs based on the PCI bus.
Here you can find the original version of David Hedley's 8086 PC emulator, and my "improved" version. This will emulate a basic PC with a VGA text-only display quite well; there is a reasonable amount of software that will work with no problems.